I bought a pH test kit last night- not sure I quite have the hang of it yet. The pond water tests 6.5, well water 7.0, and water from the rain barrel 6.2, so it looks like I may need to add a lot more lime?
From what I've read, gypsum doesn't change the pH. Is this wrong?
Gypsum is a mild base, and will raise the PH only if you add lots of it.
