Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
I also have used peat moss, not bottled additive.
Several forms of wood, especially oak but a lot of others will do this, too.
Indian Almond Leaves, oak leaves will do this.
I put peat moss in the filter about once a month. 1/2 cup of peat moss per 20 gallons, but the amount is not very critical. I also pre-treat water before I do water changes. I use a knee-hi stocking of peat moss in a garbage can of water. I re-use the peat moss several times.