I use a Culligan DI which I hook up to my bathroom sink tap. I can make DI water at the correct temp. for my fish at the rate of 1 gallon per minute into an 18 gallon tub. (Works out to 30cents Canadian per gallon.) Then I add electrolytes, pH acid buffer, alkaline buffer, black water extract and pump it out with a Rio 2500 that is attached to a Python hose. I can turn off the hose when I go from one tank to the next. I can hear when the water level is low in the tub, so I don't let the pump run dry. If I have help, then someone can just adjust the angle of the pump in the tub and I can get almost all the water out. Otherwise, the last 2 gallons I dump into a bucket. I then pump waste water from another 18 gallon tub near the fish tanks into the toilet. Works like a charm. Kind of expensive, but my fish love it. (Toronto water is hard >200ppm.) And consequently, so do I. I keep the water soft, and I don't have a white chalky build-up on the tank edges etc. I also water my plants with the waste water from the tanks, and they like the stuff too.) G. Kadar ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!