[Grete Gillebo]

I doubt pool testers would work. A pool will not reach the low pH-levels we are out to measure. They probably have no capability below a pH of around 6. That is, unless you buy a very expensive lab standard photometric analyzer. To my knowledge, there are no drop test kits that have satisfactory resolution at pH-levels much below 6. A pH-pen of reasonably good quality is a much better option, imho.