If you take my advise you will get away from kalk. I use to use it but it was a real pain. Not to mention the problems it causes with ph. I built a calcium reactor for my 125 gl reek and I don't regret it. The instructions on this site are very good. It tells you where you can purchase everything as well as approximate prices. It was very easy to build. I maintain a calcium level of 400 - 450 using this reactor. http://www.animalnetwork.com/fish2/aqfm/1998/mar/features/2/default.asp
