Join Date: Jul 2010
Location: Outside Philadelphia, PA
Using oak leaves, peat moss, and other leaves that make water acid, and decrease hardness is a classic way of softening water. This is a comparatively long, slow process and will tint the water in the process. It's great if you want your own "blackwater". IMHO, it's a pain to do and too much like work.
Also note the trend by some to change 50% of the water in the tank a week. If your using your own "blackwater" that's a lot of containers around just to make it.
I recommend you go out get an RO/DI unit. One that makes 25 to 75 gal per day should work fine for most people. The water will be clean, colorless, and all set for use. You can use a product like RO/Right if you want to build a little hardness in the water prior to use. Discus keepers and reef keepers have been using RO/DI water for years. The initial cost is about $150, which when compared to some items available in the hobby, is inexpensive. Plus, it's a lot less work.