Cory writes: > The problem I have is that > calcium carbonate does not dissolve readily and that I would have to age the > water and test it to get the right 'hardness'- with CaCl, I can add the > correct amount and have the correct doseage without testing or aging my > water Point well made. My efforts along these lines are usually to reduce alkalinity so I can push the pH down effectively. And as for your comment about the ions being surrounded by water- absolutely. Na2CO3 and CaCl, when dissolved in the same water yields ions of Ca++, Na+, Cl-, and CO3- -. To say that you have NaCl and CaCO3 is kind of presumptuous. I find it interesting that you get CaCO3 as a precipitate when you mix your two salts simutaneously, but not when you do it separately. Someday maybe I'll try it just to see. Bob ------------------------------------------------------------------------- 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"!