Hi micheal I have use kalk in the past for severale years and found it to be a very good and cheap way to maintain calcium , alkalinity and hight PH
If you use it the rong way yes it could be dangerous but any other supplement will be if you use it the rong way. people who said kalk is not good only dont know how it work
here is a couple of good tread
http://www.canreef.com/phpBB2/viewto...er=asc&start=0
http://www.canreef.com/phpBB2/viewto...highlight=kalk
http://www.canreef.com/phpBB2/viewto...highlight=kalk
you could see my set up and the reactor I use here
http://zapzap.zwf.net/gallery/Album-de-stephane?&page=1
I have now buy a calcium reactor with CO2 one month ago but still try to adjust it right the realy big draw back since I plug the puppy is my PH
is deadly low 7.9 to 8.05
If you have any question feel free to ask