Hi dmm28: I am using peat fiber in my Angelfish tank.
My source water is mixed from the one serviced by the city (unreliable and unpredictable) and a well, so I get
pH at 7.7-7.8, but variables degrees of
GH and KH.
I managed to slowly and safely drop the pH in that tank to 7.1. I just keep an eye on KH so it doesn't go below 2dKH (I feel it's safer at 2.5 or 3). If you use peat without fish in your tank it will be a lot easier to figure out amounts. It is stressful to do it with livestock in there.
I am collecting Indian Almond Tree Leaves (plenty of them for free in my city) and will experiment with that one too. I suggest you use aquarium safe peat. It's not hard to do and personally I find it safe.
I am using Fluval Peat fiber (out of market, but I found some locally). The good thing is that when peat becomes "out dated" the effect on pH is slow, gradual elevations so fish adjust without problems.
Pepe
Santo Domingo