Are digital ph/chlorine testers for pool chemistry any good?
I’ve never used litmus paper tests myself, so not sure of the reliability of those. I would presume that they are not too reliable, which seems to be true in your case if your results are fluctuating greatly I used to work for a pool where we used colour matching tests, but ours used indicator tablets. Basically we’d just bung in DPD1 and DPD3 tablets for chlorine or phenol red tablets for pH, mix it up and compare it to a chart. It was very inconsistent, as the colour I would match the sample to could be different to the colour another person would match the same sample to, usually +/- 0.2-0.4 whilst testing pH, and +/- 0.5 when testing free and total chlorine. Even when finding the colour match myself, I sometimes couldn’t match a colour and would wind up guessing! Since I’ve worked there, they have bought a digital tester – and the results of that are vastly different to the ones which are found when doing manual testing (they had differences ranging from +/- 0.5-3.0 when testing th
