The pNa is an easy-to-use and inexpensive instrument for determining water hardness/softness. The hardness of water is due to the presence of magnesium and calcium. These make washing difficult, waste soap and create unpleasant scum and scale deposits. With a zeolite system, the calcium and magnesium ions are substituted on a one-to-one basis with sodium ions from a conditioning resin. Once all the sodium ions are exhausted, the resin has to be regenerated. This is currently determined by estimating the volume of water that goes through the softener and guessing when to change the resin!
Even though this may work in some cases, it fails in most since the sodium content of feed water is never constant. As a result, either the resin is regenerated too early, and waste resources, or too late, risking damage due to scaling. With the pNa, you can measure the sodium content of feed water and exit water in seconds. When the resin is exhausted of sodium, there will be no exchange and the pNa will read the same value at the two ends. Only then should the resin be changed. pNa takes guess work out of resin regeneration!
0.0 to 3.0 pNa (23 to 0.023 g/L Na+)
manual, 1 point
Battery Type / Life
4 x 1.5V / approx. 800 hours of continuous use
0 to 50°C (32 to 122°F); RH max 95%
175 x 41 x 23 mm (6.9 x 1.6 x 0.9")
95 g (3.4 oz.)
Standard Solution at 2.3 g/L Na+ 1 x 230 mL bottle
Standard Solution at 2.3 g/L Na+ 1 x 500 mL bottle
General Purpose Cleaning Solution 1 x 230 mL bottle