Hi, Koikeepr:
I've been fighting this pH battle all spring and summer. I appreciate your response and assitance. Here's some more info:
I have city tap water - no choice here. The pH in fresh, just-out-of-the-spout water is 7.2. However, after letting it sit 24 hours to equalize, the pH is 8.2 using a drop test. I couldn't figure out why water changes weren't lowering my pH, until a chemist suggested letting the water sit. That explains that...
My pH in the evening and morning is 8.2. During the day (as stated earlier) it is at least 9.0 (test tops out here). I am familar with diurnal changes in pH, so this does not surprise me. Pond water hardness is 150 and alkalinity (KH) is at least 300 (or more...test strip so hard to tell).
I have plenty of established plants in the pond, just to name a few - anacharis, water lettuce, water hyacinth, hardy lily, and some marginals. Marginals are not growing and look bad; leaves are dying. I've read that a high pH keeps plants from absorbing nutrients.
When doing water changes or adding water to the pond, I add a dechlor and a chloramine remover made by PondCare.
I've been doing some reading on adding peat to lower pH AND hardness. So, I thought I'd try it. pH down does scare me; however, I did add it once about a month ago, and it made no difference. I don't want any crazy pH swings. Obviously, my water has good buffering.
Does a store bought pH buffer help in ponds that are already well buffered? Will the pH still have diurnal swings if I add buffer? If I could keep the pH at 8.2, that would be better.
Any ideas or suggestions are appreciated. Thanks in advance!