Hi Matt, I used to do the MgSO4 (Epsom Salt), CaCl (Calcium Chloride), NaHCO3 (Baking Soda) thing but it was time consuming and to be truthful somewhat confusing. I also found it easy to get things "out of balance" and plant growth would suffer. An alternative I would strongly recommend for people wanting to harden their tap water or "rebuild" their RO/DI water is Seachem Equilibrium which is a product specifically for planted aquariums. http://www.seachem.com/Products/product_pages/Equilibrium.html I have used it for about a month now and am very happy with the results. Wait until you see what that "empty" tank that I posted a picture of in early December looks like today! There is even a "Dose Calculator" on the right side of the page of that link to help determine how much to add to raise your dGH a specific amount based upon the gallons of water volume. Not every LFS stocks it however; I found it at Sierra Fish and Pets (Old Fish Gallery) in Renton. I still use NaHCO3 (Baking Soda) to raise my KH. Hope this helps! Roy _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member