I'm sure Pharma Can and Rhizome are correct....I say it may answer your question for this reason.....I have well water....and fish......and I could never keep the ph of my water stable with fish stuff. My hydro guy warned that could very well be a red flag for growing hydro (and it was....) ...so if you have added alot and it still climbs.....I wouldn't even try the test with reg hydro ph.....I'd just buy r/o or distilled at that point. There's NOTHING like pulling your hair out over the same ph issues again and again.....(i say from experience....:wtf Good luck.