"I was under the impression that straight RO lacks > any trace minerals fish need" Kelly very good question. This is only a concern with DI water which completly desalinates the water(Calcuim and Mg) DI water is just about 100% pure H2O, in contrast RO leaves enough "stuff" Behind that is is 100% safe for fish that come from such water as most of our Apistos do. I use 100% RO for all my Soft water fish with no reservations. "without some > kind of buffer it is given to more fluctuation in > the water parameters" Kelly this is a point of great confusion among hobbyist today. For some crazy reason many people think that very soft pure water has a problem with pH bouncing. The confusion comes from a lack of understanding the pH buffer system. First of all lets THROW the word buffer OUT! it just confuses people. A better and more correct term in my opinion is KH. Or Carbonate Hardness. The KH is of utmost importance to us Apisto keepers. If we want to regulate or change our pH we need to look at our KH. The point I am making here Kelly is that pure RO water from a high quality RO unit should have a KH of 0. Given that lowering your pH will be easily accomplished by natural methods such as Peat and Oak leaves. The so called pH crash people experience is due to a lack of water quality management. When water sits and DOC's ( phospahtes, Nitrates, etc) accumulate this all tends to acidify the water and will lower the pH more and more over time. It is my firm beleif pH crash is more often associated with people using all sorts of crazy chemicals to mess with their pH. As Don Z-man says K.I.S.S. Just use 100% RO for most Apistos this will breed them and you dont have top mess with anything just keep the water quality high via water changes. If you have a black water species a little peat some Oak leaves Faggetabout it. Keep in mind Kelly that our Little Apisto friends come from water that are almost as pure as DI water so using 100% pure RO is the common sense thing to do. I hope this helps you Kelly and nice to hear from you. Dave Sanchez --- rabidchild43 <firstname.lastname@example.org> wrote: > I was under the impression that straight RO lacks > any trace minerals fish need and that without some > kind of buffer it is given to more fluctuation in > the water parameters........Kelly > __________________________________________________ Do You Yahoo!? Great stuff seeking new owners in Yahoo! Auctions! http://auctions.yahoo.com ------------------------------------------------------------------------- This is the apistogramma mailing list, email@example.com. For instructions on how to subscribe or unsubscribe or get help, email firstname.lastname@example.org.