IME peat reduces hardness but doesn't reduce pH very much. I went from 7.8 to 7.2 using peat in my canister. However, my city dumps all kinds of crap (NaOH, etc.) in their water to keep old pipes from corroding.
This is what I've read in forums: 1) you shouldn't use charcoal for extended periods in planted tanks because it will remove some micronutrients (this is definitely true, but I don't know how much it actually affects plant growth), and 2) peat supposedly helps plants by keeping iron and/or other minerals dissolved in a form that plants can more easily use (I don't know if this is true, but it's what I've heard).
This is what I've read in forums: 1) you shouldn't use charcoal for extended periods in planted tanks because it will remove some micronutrients (this is definitely true, but I don't know how much it actually affects plant growth), and 2) peat supposedly helps plants by keeping iron and/or other minerals dissolved in a form that plants can more easily use (I don't know if this is true, but it's what I've heard).
