We’ve compiled a list of our Frequently Asked Questions to help you get the best out of your instrument and to optimise your testing process. Filter the list by your product type, application or query.

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Check standards are used to determine if an instrument is still within calibration.

Photometers work by sending light through the sample, check standards for these instruments are usually either Coloured Solutions or Neutral Density Filters (NDF). Both types have known and certified transmittance or absorbance values so they should give these values when read in a photometer. To make the checking process even simpler some instruments will convert these to a parameter such as chlorine and give the value mg/L. The ‘target’ value is on the certificate supplied with the set of Check Standards.

Kemio and sensor instrument check standards verify that the instrument correctly measures electric signals. As with electrochemical sensors in samples, the instrument applies a voltage to the check standard and measures the resulting current. Check standards include verified resistors, which produce a consistent electric current. Kemio validates the measured current internally. Sensor instruments display the corresponding concentration value, which is compared manually to target values on the certificate supplied with the set of check standards. Check standard kits come with four standards to test across the measurement range.

This will be stipulated by your local authority, and will depend on the amount the pool is used, but as a general rule;


  • Disinfectant Residual   (Chlorine, Bromine, Ozone etc.)
  • pH


  • Alkalinity
  • Calcium Hardness
  • Cyanuric Acid
  • Water Balance
  • Total Dissolved Solids


  • Sulfate
  • Turbidity
  • Microbiological

For more information on pool testing download our Pool Chemistry Guide.

Check standards allow you to confirm that your instrument is reading results correctly.

The recalibration process is a highly technical process which is carefully controlled. To recalibrate your instrument, it must be returned to Palintest. Contact your Palintest representative for more information.

All instruments must be booked in with our team prior to being sent to our office, please contact our team to arrange this.

Palintest has a dedicated technical support team who is happy to assist you with any queries. To help speed up our response and to ensure we can deal with your query as quickly as possible, please provide as much information as you can (e.g. instrument serial number, some background information to your application). To contact them, please fill in the form on this page.

To help equip you with more information to get the best out of your instrument, our team has also created a library of information which can be found in our content hub. This includes a list of best practice tips to help ensure you are performing the test correctly, to view these tips please click here. 


Check your Kemio software version on your instrument by pressing Configuration > Settings > Details.

When scanning the QR code on your Kemio sensor box, Kemio checks to see if a new software version is available. If so, it will pop up a message asking you to download and install the latest software from the website.

The latest Kemio software can be found on the downloads tab of the Kemio product page here. We recommend that you check for updates every 3 months.

Palintest regularly releases updates to Kemio software to add new test methods and improve your user experience. Usually, software updates are optional, as they provide added benefits but do not affect test results. Some updates are mandatory and you can hear about these updates by registering your product here. In these cases, tests using new batches of sensors cannot be performed until the upgrade is performed.

‘Blanking’ is how a photometer sets the zero point when conducting a test. For the majority of tests, a blank is a sample of water to be tested, with no reagent added.

Some exceptions are Tubetests that usually require the blank to be a new unused Tubetest.  COD (Chemical Oxygen Demand) requires a Tubetest to be made into a ‘blank’ by adding deionised water and digesting (heating) it, following the sample process used for a sample.  These procedures are explained in the relevant test instructions.

An instrument service covers an initial visual evaluation, run of check standards, software check and upgrade if necessary. The photometer is then recalibrated and issued with a new certificate.

Each sensor is precisely dosed with chemicals and carefully stored to deliver a high-quality measurement. Touching the electrode will affect this dosing and result in inaccurate results. Discard the sensor and use a different one.

Kemio™ Heavy Metals has the only portable EPA approved method for lead testing.

For more details, contact your Palintest representative.

The methods used for colorimetric and photometric involve an extraction process, creating a highly ionic solution. This in turn requires a slightly different formulation of colorimetric/photometric reagent than that used in water-based samples to provide effective colour development.

In summary, to measure soil parameters correctly requires the use of the soil reagents developed specifically for that purpose. We manufacture a range of soil test kits, with each specification offering a configuration designed for a different application, from simple measurement of key nutrients through to complete portable soil analysis laboratories.

We provide all the necessary parts and consumables within each kit, making it easy to select the kit you need to begin testing straight away. View each kit page on this website to see which reagents are included in each kit, and we also list the part codes of each component to aid procurement of additional and/or replacement consumables.

Kemio is IP67 rated but it should be kept clean and dry to avoid bacteria build-up. Use non-abrasive cloths and non-aggressive detergents if necessary. Be sure to dry the contacts under the front lid if wet and keep the sample vessel holding area clean.

Rinse the sample vessel between uses and clean it more thoroughly occasionally to reduce the risk of cross contamination between tests.

Turbidity is used to measure the clarity of pools and spas. This is important to ensure that swimmers, lifeguards and camera systems can see clearly through the water for safety reasons. However, it is also important to monitor the turbidity to ensure filtration systems are working effectively, and that there is not an imbalance in the chemistry of the pool.

For more information about the importance of monitoring turbidity in swimming pools and spas, read our article here.

Monopersulfate can react with the DPD total chlorine test causing a false high total test, and thus, a false combined chlorine reading. The DPD Oxystop tablet eliminates this interference allowing an accurate measurement of total chlorine. This should be used prior to the DPD #3 tablet. The DPD Oxystop tablet may also be used in exactly the same manner with the DPD XT tablets.

There are two broad categories of DBP, those which are carbon based, called C-DBPs, and those that are nitrogen based, called N-DBPs. Both of these are damaging to human health and should be controlled as much as possible.


  • THMs: Trihalomethanes
  • HAAs: Haloaceticacids
  • THAs: Trihaloacetaldehydes


  • CAMs: Chloramines
  • HANs: Haloacetonitriles

Palintest sensors cannot guarantee accurate results when they are used above the recommended temperature range.

Palintest recommends that you dilute your sample with deionised water. The dilution factor can be set on the instrument allowing it to perform the calculation for you. This ensures that the sample remains within the target concentration and temperature range of the sensor being used.

Follow the steps below:

  • Clean and dry the contacts with an alcohol wipe
  • Clean the sample pot thoroughly
  • Test a sample of deionised water

If the reading of your sample is high, please send a copy of your log file to sales@palintest.com

We have a dedicated technical support team who are happy to assist, please send your log file to sales@palintest.com for further help.

Yes. If all wells are negative for either total coliforms or E. coli the 16th well (overflow) should be inspected. If this is also negative the sample can be considered to be absent of total coliforms or E. coli, depending on the target. Any yellow or fluorescent response from the 16th well creates a result of <2 MPN/100mL.

Yes. For inland waters, it is generally okay to use the standard protocol unless a more rapid result is required. For transitional and coastal bathing waters, the sample should be diluted at least 10 times using sterile deionised water before following either protocol to avoid suppressed results due to ionic strength.

Follow either the Accelerated Protocol or Standard Protocol for results (either Presence/Absence or Most Probable Number) in 16 hours or 18 hours as a minimum incubation time respectively. Both protocol results can be read up to 48 hours after starting incubation without breaching the test method protocol, the most flexible incubation window available.

Use the Colitag Comparator (CT130), which contains certified concentrations of the ‘marker’ reagents released during the actual test. In summary, any sample which is more yellow or fluoresces more strongly than the Colitag Comparator can be considered a positive result for either or both targets.

Simply put, the microbiological media includes a component which can only be broken down by an enzyme unique to the microbiological target The key identifying features of coliforms and E. coli are their respective abilities to metabolise specific nutrients during an incubation step.

The Colitag test for E. coli does not speciate at all but gives a simple and reliable indication or quantification for all β-glucuronidase-producing E. coli. The vast majority of non-environmental E. coli produces this enzyme, making the approach ideal to detect faecal pollution derived from warm-blooded animals.

Isn’t this the same as Colilert?

A number of enzyme-based methods of detecting and enumerating Total Coliforms and E. coli were developed during a period of discovery in the late 20th century. The use of β-galactosidase and β-glucuronidase are common to most available methods but there are significant differences between approaches. Colitag™ for example uses a unique media which is specifically formulated to resuscitate damaged E. coli from chlorinated samples, avoiding dangerous False-Negative results.

A False Positive is a result indicating a detectable presence of the target organism where none are in fact present. The False Positive scenario produces a ‘fail to safety’ in most circumstances but results in unnecessary corrective action. Typical causes are poor testing technique, contamination of samples and the susceptibility of tests to interference from competing organisms. One of the most common causes of False Positive is the over-incubation of samples for methods with a narrowly defined incubation time window. Select a test method with both a minimal interference formulation and a wide incubation window to minimise False Positives.

Specifically for microbiological testing, a False Negative is a dangerous scenario. The test used declares that the target organism is not present when it is, due to issues such as poor sample mixing or the inability of the test method to effectively resuscitate and culture the target (the Viable But Not Culturable scenario). Select a method for the target organism which has a low False Negative where possible.

The SirenBW method evaluates a parameter called Endotoxin Risk (ER), a general measurement of the likely health impact of bathing water quality. Endotoxin Risk includes faecal pollution through to toxic Blue Green Algae (BGA) and covers a wide range of pathogens. The Siren method will detect the changing profile of the bathing water with respect to the likely impact on user health by reporting elevated levels of ER.

The generic name given to a group of bacteria which has the following characteristics – Gram-negative, non-spore forming, rod shaped and aerobic/facultative anaerobic bacteria. The ability to ferment lactose is key to identifying coliforms using culture methods, now simplified to the detection of β-galactosidase with the Colitag™ reagent.

Total coliform bacteria is a general description of the coliform family, specifically defined now as the ability to produce β-galactosidase to ferment lactose. Escherichia coli (E. coli) is a subset of total coliforms and previously defined as being able to produce indole from tryptophan. Nowadays the more easily identifiable presence of β-glucuronidase is used to detect and enumerate the presence of E. coli.

%T or % Transmittance is related to absorbance and is effectively the amount of light that isn’t absorbed by a solution at a particular wavelength and path length. So, if all the light passes through a solution without any absorption, then absorbance is zero, and %T is 100%. If all the light is absorbed, then %T is zero, and absorption is infinite.

Palintest Check Standards are traceable reference materials defined in terms of %T at a particular wavelength and are ideal in confirming your photometer is conforming to specification in the field.

All instruments must be booked in for a service before arriving back at Palintest. This ensures that we can track your instrument and schedule instrument services in the most efficient way. Any instruments not booked in before shipping, are likely to be subject to delays

In certain circumstances Palintest is able to offer on-site servicing for selected facilities in the UK. Please contact our team if you would like to discuss this option.

We recommend that only your instrument is returned, to prevent any losses or damages during transit.

Total Dissolved Solids (TDS) describes to the solid particles that can pass through a 2-micron filter. The solids in a liquid that cannot pass through this filter, i.e. the larger particles, are described as suspended solids. Particles that are even larger are known as settleable solids.

As not all ions move at the same speed, have the same charge density, or are the same size, they all conduct electricity at the different rates. The TDS factors are a fudge factor which accounts for this variability when converting a conductivity measurement to a Total Dissolved Solids (TDS) measurement. There are different TDS factors for different water types.

Water Sample Type TDS Factor
Saline Swimming Pool 0.55
Typical Swimming Pool 0.67
Drinking Water 0.71


Palintest Soil Test Kits are designed to allow field testing of soil samples which should be comparable to standard laboratory methods.

All Palintest soil extraction methods are based on the method recommended in the UK by MAFF/ADAS ‘The Analysis of Agricultural Materials’ Reference book 427 where possible.

Test Species Palintest Extractant MAFF/ADAS Extractions
Nitrate N 1M Ammonium Chloride 2M Potassium Chloride
Phosphate P 0.5M Sodium Bicarbonate 0.5M Sodium Bicarbonate
Potassium K 0.1M Magnesium Acetate 1M Ammonium Nitrate
Calcium Ca 1M Potassium Chloride 1M Ammonium Nitrate
Magnesium Mg 1M Potassium Chloride 1M Ammonium Nitrate
Aluminium Al 1M Potassium Chloride No method
Ammonia N 1M Potassium Chloride 2M Potassium Chloride
Chloride Cl Water Saturated Calcium Sulphate Solution
Copper Cu 0.05M Disodium EDTA 0.05M Ammonium EDTA
Iron FE 1M Potassium Chloride No method
Manganese Mn 1M Ammonium Chloride 1M Ammonium Acetate
Conductivity mS/cm Water Saturated Calcium Sulphate Solution
Sulphate S Water Water
pH pH No extraction required No extraction required

Kemio is designed for the analysis of water samples. Palintest does not recommend the use of our sensor products for analysis of oils.

Please contact a member of our team for further help, we have a dedicated technical support team who are happy to assist. To help speed up our response and to ensure we can deal with your query as quickly as possible, please provide as much information as you can (e.g. instrument serial number). To contact our team, please fill in the form on this page.

Clean and dry the contacts with an alcohol wipe or lint-free cloth and then repeat the test three times. If the problem persists, please send your log file to sales@palintest.com.

  • Thoroughly clean and dry the contacts with an alcohol wipe or lint-free cloth.
  • Ensure the check standards are clean and dry.
  • Check you have the latest Kemio software. If the software needs updating download and install the latest version from our website. The latest Kemio software can be found on the downloads tab of the Kemio product page here.

Once all the above steps have been completed repeat the test three times. If the problem persists, please send the log file to sales@palintest.com

Yes, the active ingredient of Palintest’s Instachlor tablets, Sodium Dichloroisocyanurate Anhydrous (also known as Troclosene Sodium and NaDCC), is sourced from suppliers listed in the ‘Article 95 list’ of the Biocidal Products Regulation ((EU) No 528/2012 (BPR)) and applies to product types PT2, PT3, PT4, PT5 and PT11.

The active ingredient of Palintest’s Steadichlor tablets, Calcium Hypochlorite, is sourced from suppliers in the ‘Article 95 list’ of the Biocidal Products Regulation ((EU) No 528/2012 (BPR)) covering all product types listed for the active ingredient.

From 1 September 2015, a biocidal product cannot be made available on the EU market unless either the substance supplier or the product supplier is included in the Article 95 list for their active substance in the relevant product type.

Ensure the device is off. Plug the USB cable in to the PC. Power on the instrument. Wait 30 seconds for the device to re-enumerate. Drag the file called CLSE_LOG.txt to the desktop. Open the file in excel to view the data in columns.

Certain operating systems are not compatible with sensor instruments. If the log file is still unavailable, contact your Palintest representative for support.

Kemio uses the same technology to the sensor technology range, but the calibration method is different. Kemio sensors may give a result on your instrument, but it will not be accurate, as it is using the wrong batch information.

Kemio uses the same technology to the sensor technology range, but the calibration method is different. Sensors for these instruments may produce a result on your Kemio, but it will not be accurate, as it is using the wrong batch information.

Kemio accepts a maximum of 20 labels per test type. Unused labels can be deleted to free up space.

If your application has more than 20 ways of grouping tests, consider setting more general labels, and use a note or scanned reference barcode after the test to identify the test more specifically.

A sensor batch’s information must be added before performing a test with a sensor from that batch. Scan in the QR code under Configuration > Batch Information > Add Batch Information.

Kemio will only accept a sensor barcode that is suitable for the selected test, for example, a PAA sensor will be rejected if a Chlorine test is selected. Please ensure you are using the correct sensor for the selected test.

If the problem persists, please contact a member of our team.

Make sure the red dot is centred on the barcode. The barcode should be about 12 cm away from the scanner. Tilt the sensor, or move it closer or further away from the scanner to find the ideal distance. If a barcode is not scanned after five seconds, Kemio shuts off the scanner to save power.

The scanner may also be affected by dust or water marks on the plastic protective cover. Clean the screen to ensure that the scanner can read the barcode properly.

If the problem persists, please contact your Palintest representative.

Error messages indicate that something is wrong with the instrument or methodology. Some error messages are a warning and will still allow you to perform tests. For other error messages, you will be unable to perform a test until the error is corrected.

If you are unable to resolve the error and perform a test, contact your Palintest representative for assistance.

Each sensor is precisely dosed with chemicals and carefully stored to deliver a high-quality measurement. Touching the electrode will affect this dosing and result in inaccurate results. Discard the sensor and use a different one.

Vibrations while Kemio is performing a measurement may cause an inaccurate result. Prevent any sudden or continuous movement of the instrument during a test.

A stylus pen is provided with Kemio to make typing on Kemio easier. When in contact with water, the screen will still work but will not be as responsive. Dry the screen to improve responsiveness.

The touch screen is not as sensitive as a smart phone, and each touch should be held for slightly longer. On the keyboard ensure the correct key pops up.

If you continue to have problems, please contact your Palintest representative.

The USB cable supplied with Kemio will transmit both power and data, a regular micro USB cable can also be used. Some USB cables available on the market are only suitable for charging your instrument.

When using a Mac, a file management software that mimics Windows is required. One potential solution is https://itunes.apple.com/us/app/commander-one-pro-ftp-client/id1035237815?mt=12.

If you continue to have trouble using the USB cable supplied with your Kemio instrument, please contact your Palintest representative.

Kemio is a multi-parameter instrument. Each batch of sensors has its unique batch calibration information. Scanning the sensor allows Kemio to select the correct test type and use the specific batch information. Using the correct batch is imperative to ensure the accuracy of your results.

To perform additional tests using a sensor from the same batch, you can select ‘retest’ after performing a test. Alternatively, you can change your scanning settings from Configuration > Settings > Test Settings > Scanner Settings.

Kemio is flexible platform which enables you to perform multiple tests and enrich your data with additional information for each test.

You can also simplify your tests and choices. Select only the tests you require from Configuration > Select Tests. To change the process of assigning users and labels you can change your settings from Configuration > Settings > Test Settings. Unnecessary labels or users can be deleted from Configuration > Labels and Configuration > Users.

Kemio enables you to use labels and set high and/or low limits. If results are within these limits then a PASS result will appear. When a FAIL result appears it is because the concentration falls outside of your defined limits. Use this information to adjust your process or take corrective action if necessary.

If you get an unexpected result from your Kemio or sensor instrument, you should perform the test again. If a similar result appears on the re-test, you should perform the following checks:

  • Run the check standards to confirm if the instrument is performing measurements correctly.
  • Check the use-by date of sensors.
  • Check that the correct batch code is being used with the correct sensors.
  • Check that the test is not being performed on a vibrating surface.

If you continue to have trouble following these steps, please contact your Palintest representative.

The WFD is a legal framework that ensures the restoration of clean water across Europe and ensures its long-term sustainable use. The changes to the WFD in 2018 reduced the permitted amounts of many pollutants in surface waters. This is especially important for the 33 priority substances.


Disinfection by-products (DBPs) is a term used to describe all the molecules generated as a result of any disinfection processing of water. For the most part this is key in drinking water, pool & spa water, and in industrial wash waters but can be important in other industrial applications too.

Generally, DBPs are responsible for any irritation of the eyes and lungs when near or in disinfection-controlled water, and will also contribute to asthma, especially in children. Additionally, there is significant evidence that many DBPs are carcinogenic, meaning they will increase the likelihood of cancers in those exposed to them.

It is important to monitor both the water quality, and also the air quality if the water is in an enclosed space, for example an indoor pool. This is because DBPs are volatile compounds, meaning they will easily get into the air from the water.

There’s a place for both techniques when carrying out quantification of microbiological water quality. Membrane filtration is particularly focused on the quantification of samples with less than 200 CFU/100mL. The Most Probable Number approach enables higher limits of detection to be reached and is generally simpler to execute. For example, the MPNplate™ has a working range from 0 – 1600 MPN/100mL and the unique roller sealing approach enables use in the field without requiring laboratory hardware.

The Most Probable Number (MPN, also called the MTF technique) is a US EPA (Method 9131) and ISO (9308-2) approved method to statistically predict the number of Coliforms present in a sample. This is done by comparing how many positive results (i.e. Coliforms are present) are obtained across a dilution series.

Three dilutions of the sample must be used, and five repeats of each are required. The tubes are all incubated for 24 h at 37 °C, and the number of positive results for each dilution is used to determine the MPN using the MPN Index. Usually a positive tube is indicated by a colour change.

The membrane filtration (MF) method can be used to reliably test large numbers of water sample, and is US EPA approved for measuring coliforms.

The water sample is filtered through the membrane filter using a vacuum to pull the water through the membrane. The membrane filter is then placed onto a nutrient source gel in a petri dish and incubated for 24 h at 37 °C. The Coliform and non-Coliform colonies can then be counted. Often pH indicators are used to distinguish between different colony types.

The size, location and amount of use your pool sees will impact which disinfectant system is most suitable. All disinfection systems have advantages and disadvantages.

Palintest always recommend that you consult your local authority to determine the correct disinfectant level for your water.

There are no overarching global regulations for the fresh produce washing industry, as each produce type must have a different wash process. Fresh produce washing process must result in produce being sold that causes no harm to consumer. The wash system design, organic loading, pesticides and water recirculation will have a significant effect on the required sanitizer levels. Palintest recommends consulting a local food safety professional who will conduct a risk management decision for your particular system.

The method detection limit or MDL is a measure of the lowest concentration that can be detected using the exact method, this takes into account the instrument as well as the chemistry.

Palintest quote an MDL rather than an LOD for their products. This is more representative of what can be expected when carrying out a test using one of our instruments.

Very high free chlorine residual can cause bleaching of the pink coloration in the DPD free chlorine test.  This gives a false low result.  A dilution can be performed to find the actual chlorine level.

View our chlorine parameter page here.

The calcium hardness test has been formulated not to be influenced by other metals in the water, and is therefore not affected by the presence of magnesium.

Palintest phenol red pH tablets are formulated to include a chlorine neutralizer (thiosulfate).  This prevents any interference from chlorine at levels used in pools and spas.

Error messages usually indicate that your photometer has detected that something that might affect the result of a test.  Some error messages are a warning and will still allow you to perform tests.  For others, the error will be considered critical and the instrument will prevent a test being performed.

Please check your instrument’s User Manual for details of what the error message means.

Photometers should be regularly cleaned to ensure that your instrument is reading correctly and is not affected by dust or water marks.

To clean a compact photometer, place a small amount of anti- static cleaning foam on to a lint free cloth and wipe the instrument.

For multiparameter photometers, you should clean several parts of your instrument. To clean, place a small amount of anti- static cleaning foam on to a lint free cloth and wipe the instrument.

  1. Sample holder.
    The first image shows the surface around the sample holder, all visible marks on this area should be removed
  2. Outside optics base plate.
    Turn the instrument over and undo the two screws on the base of the instrument, as demonstrated in the second image. Gently wipe the curved areas near the LEDs and the flat area on the opposite side.
  3. Inside optics base plate
    Contamination on the inside of the base plate can migrate onto your calibration tubes leading to scratches which damage the standards. If marks cannot be removed from the base plate, a new base plate should be fitted.
    When refitting or replacing a base plate, you must ensure screws are tightened so that the standards are set are the correct height. Failure to do so can lead to compromised results.

No, only Palintest approved service centres can recalibrate your instrument using calibration standards. Contact your Palintest representative for more information.

Read more about the process of calibrating a photometer here.

Palintest recommend that instruments are serviced on a yearly basis. The notification is built into the photometer to remind you that your instrument is due a service. To disable the notification, with the instrument switched on, restart the instrument consecutively three times. Please note that once the reminder has been disabled, it will not show again unless this is reset by Palintest’s service department.

If you are interested in knowing more about our service offering, click here. 

While most Palintest photometric tests use a colour based chemical reaction there are a few that use the formation of a precipitate. These make the solution cloudy (turbid) in proportion to the level of analyte being measured.

Samples from every batch of Palintest comparator discs have their colours assessed against reference colours and real chemical testing.  Samples of each manufactured batch of discs are also retained for future reference. View the Contour Comparator here.

The Palintest turbidity tube has graduations between 30 to 500 turbidity units, with an optional additional tube from 5 to 25 turbidity units.

To assess water samples, hold the tube vertically over a white surface and view downwards.  Whilst looking at the black cross at the bottom of the tube gradually pour in water.  Stop immediately when the cross is no longer visible. Read off the graduation corresponding to the height of the sample in the tube.  This represents the turbidity of the water sample in Jackson Turbidity Units (JTU).

View our turbidity parameter page here.

The discs used in our Contour Comparator kits are produced from fade-free acetate and inks.  The colour acetate petal discs are designed to be accurate for 10 years, providing they are stored in a cool, dark place.  Continuous exposure to intense UV light sources (such as daylight) may cause premature colour fading.  The outer clear plastic casing can become blemished or stained if exposed to solvents, chemical reagents or abrasive surfaces and affect the result.

Comparators can be affected by:-

  • Human judgement of colour.
  • Background Colour affecting colour perception
  • Type of Light used (Daylight, Florescent, LED)
  • Intensity of Light used (Outdoor Sunlight can be up to 10000x stronger than indoor florescent).

Photometers are unaffected by the above but can be affected by

  • Turbidity in the sample
  • Any marks or stains on glassware

Contamination or staining in the optical holder

Soils are often described as acidic, neutral or alkaline.  Soil pH values around pH 7 are neutral, below pH 7 are acidic and above pH 7 are alkaline.  pH is important as it influences the availability of essential nutrients.  Crops can exhibit deficiency symptoms in soils where there are adequate concentrations of  nutrients but due to pH conditions they are less available for absorption by plants.

CEC is the total capacity of a soil to hold exchangeable cations.  CEC is an inherent soil characteristic and is difficult to alter significantly.  It influences the soil’s ability to hold onto essential nutrients and provides a buffer against acidification.

The Lime Requirement of a soil is the quantity of liming material required to raise the soil pH to a value defined by soil type and crop requirements.  The value given by the test is the amount of calcium carbonate required to raise a 20cm depth of soil to the required pH.  Standard target values for specific soils are:

Mineral soil pH 6.5

Organic soil pH 6.2

Peaty soil pH 5.8

Target nutrients will be in soluble form after the extraction stage, enabling effective reaction with test reagents.  The presence of particulates in the test sample can interfere with the reaction, producing spurious results.  In addition, any particulates present will affect the light path through the sample, scattering light and producing inaccurate readings.  Filtration will remove particulates, allowing reaction with only the target analytes, producing representative test data.

The critical step in any analysis is taking representative samples.  Nutrient distribution across an area can be extremely variable, so it is good practice to test a composite of a number of individual soil samples.  Separate samples should be collected from each area of differing soil type, previous cropping history or soil management.  Be sure to test any areas of particular concern specifically for more detailed analysis.

Regular testing helps develop and maintain more productive soils for farming, gardening and landscaping.  Soil tests indicate plant nutrient levels and the required dose rates for optimum growth.  Soil testing is also a useful diagnostic tool for identifying problems related to excessive levels of nutrients and salts, adverse pH conditions, low organic matter and poor drainage.

When turning the instrument on, hold down the On button to toggle between turning on/deactivating the backlight.

On the main menu select System Mode within here you can select the Backlight tab. Here you can set the backlight to Off or On.

  1. Try turning the backlight off as this uses a higher current level.  This can become particularly significant when the timer is being used. See your user manual or FAQ How do I turn the backlight of a Multiparameter Benchtop Photometer on or off?
  2. Contamination in the optical cell requires the battery to provide more power to get sufficient light through the sample cell.  Please try cleaning the optical windows in the cell holder.   Use a soft cloth and water based anti-static foam cleaner.  Benchtop Photometers have a removable plate under the optic cell to facilitate cleaning.
  3. Check the inside of the battery compartment for signs of moisture ingress.  Clean this thoroughly and be sure to fit the battery cover and gasket correctly when changing batteries to ensure a watertight seal.

The digital electronics, optics and sensor systems in Palintest photometers are designed to give highly repeatable results.  If this appears not to be the case, then we would recommend using ‘check standards’ to determine whether the cause is due to the photometer or the sample.

If good results are not obtained with the check standards, please see FAQ: What should I do if check standards indicate my photometer requires recalibration?

If the check standards give good results then it is likely that there is something in the sample solution or sample tube that is causing a variation in the light passing through it.  Please, therefore, try the following:

  • Thoroughly clean all apparatus used for the test, this includes glassware, lids, crushing rods and syringes.
  • Carry out the same test several times on the same sample source, this will reduce the possibility of cross contamination from other test reagents.
  • Immediately prior to blanking or reading, cap all tubes with a clean cap. Then, holding the tubes horizontally, rotate as shown. This will remove bubbles from the glass walls.

If you continue to have issues following these steps, please contact your Palintest representative.

To help speed up the process we request that you provide details of the equipment, the test and reagents you are using; along with any information about the source of the sample being tested.

Photometers are used in conjunction with Palintest reagents. To search for reagents click here.

In addition, Palintest offer a range of accessories which can be used with our equipment, such as dilution tubes, samples tubes and tube racks. Visit accessories and check standards for more information.

If reagents require the use of additional accessories these are supplied in reagent packs with a ‘PM’ part number.

‘Analyte’ and ‘Parameter’ are scientific terms for something you want to measure.  For example, the analyte may be nitrate and as a parameter it would be nitrate concentration. Take a look at our parameter pages which include an overview of the test parameter, it’s presence in different applications and information on testing.

‘Species’ is used to refer to the atom, molecule or part of a molecule being tested for. In the nitrate example above, the result could be given as N or as NO3. It is important to be specific, especially when comparing different results.

‘Units’ refer to what the result’s numbers are.  Commonly, we use milligrams per litre (abbreviated to mg/L).  Parts per million (ppm) is also used as an equivalent in many industries.

Reagents are the chemicals we incorporate in to our tablets (and in some cases liquids or powders) which are needed as the fundamental components of the test.

If you imagine colour change taking place after 6 drops, you would multiply by 40 to give 240 mg/L.  However, 5 drops would have been equivalent to 200 mg/L.  So, the ‘true’ level is anywhere between 200 and 240.  By subtracting 20 from the higher figure you get a result of 220 which will be within 20 mg/L of wherever the ‘true’ figure is.

The turbidity (cloudiness) is usually produced by adding reagents to the sample.  To assess the level of turbidity, the depth of liquid needed to obscure a black cross or dot is then judged by eye.  Special tubes are usually supplied with this type of test. View visual tests here.

Presence/Absence tests confirm the existence of chemicals or microbes in a sample but do not indicate how much is present. In its simplest form a single tablet is added and the sample will produce a colour, or go cloudy, to indicate the result.

Typical uses might be checking that there is no hardness present in the outflow of a water softener or that there is some corrosion inhibitor still present in a cooling system.

Liquid drops or tablets are added to the sample and counted until a colour change occurs in the sample.  When this happens the number of tablets or drops used is multiplied by a factor to give a concentration.

These use a disc or a chart with coloured panels, each labelled with a figure. Normally, tablet reagents are added to the sample and the colour that develops is matched to a panel on the chart or disc. View visual test methods here.

Test Strips also use the principle of colour matching.  The reagents are already present on the test strip.  You simply dip them in the sample and compare the colour to a chart on the container.

Visual test methods refer to any method not using an electronic instrument as a visual method.  They fall in to four basic methods:

  • Colour Matching
  • Droplet or Tablet Counting
  • Presence or Absence
  • Development of Turbidity

The reasons for carrying out a test, the situation and the application all effect the choice of what test method is best for you.

For example, whilst accuracy and repeatability might be the most important factors in a modern laboratory.  Weight, speed of test, and the lack of requirement for electricity might be more important in a field expedition.

If your readings indicate that the instrument is ‘out of calibration’ you will need to contact Palintest or your local Palintest Distributor to arrange for servicing and recalibration of your instrument.

However, there are a few things you can try first.  We would recommend that you carefully clean the photometer, especially the cell holder and optical windows (NB: use a soft cloth and water-based antistatic foam cleaner).  Then try re-reading the standards.

Please also carefully check the following:

  • That the date on the standards’ certificate hasn’t expired.
  • That your instrument is listed on the certificate.
  • That the serial numbers on the standards match those on the certificate
  • That the standards are in good condition (no scratching or staining).

If these are not correct we would recommend first obtaining a new set of check standards for your instrument.

Important: If returning an instrument to our service department please let us know that the instrument is incorrectly reading the check standards with details of the part and serial numbers of the standards and which of them is failing to read correctly.

A Neutral Density Filter is an optical filter that absorbs light of all wavelengths to the same extent.  This means that if you look through an NDF it causes dimming but no change in colour.  Therefore, they are very predictable when used us check standards in optical instruments.  Being made of glass they are also stable and non-hazardous.

IP67 means that the internal electronics of the instrument are protected and will still function if it is splashed or dropped into water.

The Ingress Protection rating shows the degrees of protection from solid objects and liquids. The first number, ‘6’ refers to the protection against solids and indicates total protection from ingress of dust. The second number, ‘7’ refers to liquids and indicates protection against immersion in 1 metre deep  for 30 minutes.

Please be aware that persistent excessive humidity is different and over time, can penetrate seals and gaskets in the casework of an instrument. Should the foam inside the carry case become wet, we strongly recommend that you allow the foam to dry out before using it again for your instrument.

Colorimetry is a method of determining the concentration of a coloured compound in solution by measuring the absorbance of light passing through it.

Palintest Photometers are electronic colorimeters that have internal calibrations to convert the measurement of light absorbed by a sample into actual concentrations.

No one test is available to confirm that water is safe to drink.  There are tests that can be used as ‘probable’ indicators that water is unsafe, such as turbidity.

Water Safety is best achieved through good management practices.  Palintest offer a range of testing equipment used by Water Utilities to facilitate this good practice, such as for levels of disinfectants, potential contaminants and pathogens.

Palintest methods have published levels for limit of detection, limit of quantitation, and result tolerances which incorporate accuracy and precision.  These terms all have specific statistical meaning and definitions.  Please follow this link for an explanation of these terms

The designated bathing water sample point is usually identified by signage for each location and a sample can be taken anywhere along the transept. For SirenBW the designated bathing water sample point can continue to be used or other higher risk sample locations can be included to understand more intensely the nature of risk to bathing water users. Samples should be taken at least 30cm below the surface of the water and avoid capture of solid particles where possible. Read more about SirenBW here.

The science behind the Siren method is a patented variation of the classic endotoxin assay used to validate the safety of pharmaceuticals and other products where safety is critical. The method detects the presence of lipopolysaccharide (LPS), the underlying cause of an inflammatory or immune response to the presence of toxic substances or pathogens. Palintest has integrated the core science into a field-ready colorimetric assay for bathing water quality risk screening within the SirenBW kit.

E.coli  is one of the two parameters used to define the quality of a bathing water due to its ability to indicate the likely presence of faecal contamination. The Siren method is calibrated using an E. coli standard and there is a linear relationship between E. coli and Endotoxin Risk. It is important to remember however that the Siren assay will detect additional pathogens as well as E. coli.

The presence of Intestinal Enterococci is the second of two parameters used to classify bathing water quality according to the European Union Bathing Water Directive, the first being E. coli. The direct relationship between Intestinal Enterococci and the Endotoxin Risk reported by the Siren method is a weak one due to the small concentration of the active lipopolysaccharide (LPS) sites available for detection. However, a situation where high levels of Intestinal Enterococci and low levels of LPS are present is extremely unlikely to occur.

Endotoxin is a generic term for any harmful species that will create an immune response when ingested or otherwise internally assimilated or come into contact. The range of harmful effects that will be produced when endotoxins are present depends on the concentration of lipopolysaccharide on the invasive species and can range from minor rashes to significant gastro-intestinal illnesses.

Due to the impact of salinity on the assay, it is necessary to dilute the sample 100 times with pyrogen-free water. The method requires only 100µL of diluted sample for each test.

The stability of hydrated reagents is relatively short, lasting around 8 – 10 hours in moderate to warm ambient temperatures due to the enzymatic nature of the assay. Validating the performance of the assay by substituting Reagent X for a sample will ensure that any offset in reagent response can be effectively captured.

The Siren method detects all species that are capable of causing adverse health responses, ranging from skin rash to gastro-intestinal illness. A nominal scale of 0 -10,000 has been created to enable semi-quantitative expression of the results in terms of an Endotoxin Risk or ER. Put simply, the higher the ER value the higher the likelihood that unwelcome health impacts will arise from bathing water quality.

These are large molecules found on the outer surface of the cell membrane of Gram-negative bacteria. The biological process through which immune responses and inflammatory illnesses arise is driven by the presence of LPS, found with highest concentration on the outer surface of significant pathogens such as E. coli.

Because the Siren method is not a culture approach, a representative sample is not constrained by the requirement to capture at least one cell to reproduce. The probability of finding detectable concentrations of LPS within even 10µL are significant enough to make this volume acceptable for bathing water quality trending and source tracking studies.

A pyrogen is a substance which can cause a fever and can be fatal. The underlying cause of the fever is the presence of lipopolysaccharides (LPS), the active material detected and quantified by the Siren method. It is important that all hardware used in the Siren assay is classified as pyrogen-free to avoid false positives.

The SirenBW kit contains sufficient reagents to carry out 16 tests. Replacement reagents are available in 16 or 32 test pack sizes.

The reagents are delivered in a lyophilised (dried) format for long-term stability of up to 18 months. The expiry date is clearly indicated on the product label.

The Pota Pal application is available in both Windows and Android format. The application will allow the data for the incubation temperature profile to be downloaded and upload of new firmware for bug resolution. Both versions of software require a USB connection to the incubator, with the Android version (V4.4 or higher) requiring a ‘USB-To-Go’ cable. Contact Palintest for more information.

Yes, it is rated as IP67 which means it can withstand immersion for up to 30 minutes at 1 metre depth.

The sharing of data for bathing water quality is one of the key targets for bathing water regulators with historical data published on websites and apps. The QR code captures the result and the Compact Siren Meter meta data (serial number, firmware number) for inclusion into future developments in data sharing.

No, the SirenBW is an active management approach to recreational water quality risk for users, enabling rapid identification of deteriorating bathing water quality at the point of use in less than 30 minutes. The E. coli and Intestinal Enterococci testing that takes place for compliance reporting and benchmarking during the bathing water season is a passive activity reporting data after the event.

There is no specific time or date to take the bathing water sample for SirenBW testing. The Bathing Water Directive 2008 prescribes a weekly or fortnightly sample with more frequent sampling required during low bathing water quality or during/after weather events for compliance reporting. As the SirenBW method is not for compliance reporting it can be used either as an active bathing water quality management tool or as an intense response to incidents or both.

The SirenBW method evaluates a parameter called Endotoxin Risk (ER), a general measurement of the likely health impact of bathing water quality. Endotoxin Risk includes faecal pollution through to toxic Blue Green Algae (BGA) and covers a wide range of pathogens. The Siren method will detect the changing profile of the bathing water with respect to the likely impact on user health by reporting elevated levels of ER.

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