I thought I remember reading something somewhere about the reason people use Oak leaves is that they leach off tanic acids into the tank which naturally lowers the pH of the water. I heard this was done with some fish that needed much softer acidic water than other species. I have a friend who uses the Oak leaves in most of his spawning tanks for his dwarf cichlids. His water isn't as soft as mine but he ends up with good success using his methods. He also collects rain water to use in some of his tanks. He swears by it. John ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!