I always enjoy the comments regarding RO "WASTE" water! I hope by using that word "waste" you are not dumping it out and losing it. I have a unit that produces 25 gallons per day with "non-RO" water at 125 gallons ratio for about seven years now. I maintain 80 tanks with an average of about 15 gallons. The RO water is used only for breeding Apistos and all the other water is used for all other tanks. When I sell Apisto's to the local store, they are in regular tap "waste" water to avoid stress as I know the store doesn't use it's RO water for the sales tanks. At least 75% of my tanks use the so-called waste water. My tap water is 170ppm and the waste water is still 170ppm. There is never any added hardness in any RO system; that's what the filters are for. I actually keep 10 to 15 gallons of that water in 1-gallon milk type containers for all our cooking needs and it makes great coffee! Why the words "waste water" are used, I'll never know. If you use the water from your tap, why wouldn't you use this water where all the small unseen particales are removed and it's a lot purer? Z-Man ------------------------------------------------------------------------- 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"!