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
My instrument is IP67 rated, what does this mean?
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.
What is the difference between Total Dissolved Solids and Suspended Solids?
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.