I just put fish into a new "low tech" tank that I set up using potting soil, and cuttings from my "high tech" tank. I then read the bag the soil came in, and it is all organic, including the bat guano and chopped worms. Anyone had luck with bat guano and the like in their substrate? I don't like killing fish. David Brown --- StripMime Report -- processed MIME parts --- multipart/alternative text/html ---