Peat

The problem with putting peat in the tank itself is you get a spike in ph whenever you do a water change. You're a lot better off soaking peat water in another container. Maybe garbage-can size? That way when you do a water change the ph will be close to whatever is in your tank. If it's too acid, you can mix in some fresh water to adjust it.
 
I have to agree with the garbage can size peat water holding idea. I put peat in my filter and although my fish have survived the pH swings, it makes me nervous so I'm removing it.
 
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