Well…can it be done? I had a digital PH meter, but the thing went on the fritz and began giving impossible results even when calibrated (gave a PH of 7.8 for a tank with low 40’s microsiemens and dark brown with tannins!), so I tossed it. It would be better, in my eyes, to have something disposable but functional instead of something that will sooner or later stop working when you need it most.
I think the best way to deal with it is to obtain some better quality digital device and learn how to take care of the electrode. It takes just about the same time as the use of drop test, but you get much more accurate readings. If you sum the money spent on higher quality drop tests over time, it may be even much cheaper. The pool stuff may not even measure in the range needed for Paro tanks. + it is always hard to use drop tests in dark stained water.
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.
I wasn’t talking about paper strip tests at all, but drop test kits. Strips are quite unreliable and prone to all kinds of errors.
Drop test kits that measure down to pH 4 are available, but with low resolution (0.5). The wider the drop test’s measurement range, the lower the resolution and accuracy.