I live in Florida where my tap is measuring around 200ppm tds. Interestingly I cannot get my Moina cultures to survive in even aged tap water. I discovered that the cultures appear to be more productive in rainwater. I have been collecting rainwater for the tanks but that is unreliable. I guess I could soften the tap with peat. It just seems that an RO unit would be more convenient. -Brett ------------------------------------------------------------------------- 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"!