calcium rocks

[dkling]

Have any of you heard about these rocks that you just drop into the tank and leach calcium into the tank. I was at one of our LFS.s yesterday getting my firsy sps frag and the owner offereed me a peice of this white flat rock that he says is great for adding cal. into the tank. its in my sump now .
Ive never heard about this .

[ReefNeck]

Thats a new one on me even being around the fish business all the time. Does not mean it's not for real....Just that I have not heard of it. Would be interesting. If you find out any more, Keep us informed. I'll also check with my sources.