We have very hard water here. I used to try and try and try to adjust the PH of the water to what everyone told me was the "normal" range for tropical fish. It was a losing battle. In a few days, the water would be back to the original PH. It made no logical sense ... it was the same water, nothing new added. No wood or shells or untreated rocks, all of which can affect PH. Complete mystery.

I finally gave up. My fish are living and thriving in water so hard it should technically kill them all.