In a message dated 10/16/00 5:24:30 PM Mountain Daylight Time, emartina@uiuc.edu writes: > I am going to test my rocks and gravel tomorrow to see if they are causing > the buffering. I am concerned about using muriatic acid, since if I test a > specific rock and find it is not the problem I would like to put it back in > the tank. And I am worried that I won't be able to rinse all of the acid > off. Would vinegar be safer? Will it even work? Thanks! Vinegar works, but not as clearly. The muriatic acid is a 28-31% solution of hydrochloric acid in water. That's all that's in it. I use it to make my own pH down. It will be fine if you don't get it all off. It will simply drop the pH, probably abot .00001. Vinegar is so weak it doesn't always indicate clearly or at all. And I would worry more about getting the other stuff in vinegar into my water than I would muriatic acid. Bob Dixon ------------------------------------------------------------------------- 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"!