Kathy, Look in the local Yellow pages. I bought my supply about two years ago from a chemical company (name?) located in Renton. I've been using it in my 45 and 100 gallon plant tanks to buffer the kh and gh. I paid around $20 for a large container of it and I figure have at least another three years worth of it. Dan -----Original Message----- From: Kathy Olson [mailto:kathy@thekrib.com] Sent: Monday, January 28, 2002 6:30 PM To: gsas-member@pulcher.thekrib.com; gsas-board@pulcher.thekrib.com Subject: Calcium Carbonate Hi, I know in the past we have gotten our Calcium carbonate for our African Rift Lake Cichlids from All World Scientific. Has anyone discovered another source to find calcium/mag to harden water?? I know we have the stuff at the fish stores, but I wanted something cheaper than that!! Kathy