Does anyone know if the multi-parameters test kits, ie the ones that you use droppers for to measure ph, nitrate, nitrite, ammonie etc ever expire or go bad. I bought a kit 2 years ago and still have some of the chemicals. I have taken readings and the had the lfs sample the same water and weve gotten 2 completely different readings. I am wondering if mine (most likely) or their test chemicals could have gone bad?
