If it's just one small rock and you don't want to go around guessing where it went to hide off in or if it's completely overtaken the rock, I don't see what the big deal is. To get rid of aptasia I pulled the rock and blasted the thing with hot water - not really boiling but enough to make it wilt and I scraped it out - while i didn't totally kill the "live-ness" of it, i'm sure it set back my cycle a bit but so what! Personally, I'd rather have one base rock than put exactly the right amount of kalk mix in the right place. Also, what if you don't want a peppermint shrimp?! ah ha! (whistle) (laugh) Whatever works out in the end is the right way and it looks like kalk worked out for you so good! the end. (laugh)