My emerald crabs liked bubble algae...until the coral banded shrimp took them out, of course. For the aiptasia, you could go the *tough* route if you wanted to kill it off (which most people do?). Mix up some kalk and squirt it directly into their mouths. That kills 'em pretty quickly. Or else you can try a peppermint shrimp. While I had mine around, he ate up every bit of aiptasia like it was candy.
I'd be careful about setting the rocks out to dry if they've got corraline algae on them that you'd like to keep - it would also die off and the colors would be gone, I'd think. If you're not worried about THAT, then you could simply set them all into bleach water, kill the rock itself and everything on it, and then cycle it again. *shrug* It'd certainly take care of everything!
- Bekah