[TroyPierce]

Believe it or not, I use a strong lye solution to kill unwanted growth. It doesn't take much and organic matter will disolve like it was dunked in acid.

I mix a stong solution of powdered Draino (100% lye) in a small GLASS container (Careful, it gets HOT) and use a small syringe and needle (used for injecting cats with insolin). Take the rock from the tank if you can, inject a very small amount into the 'thing' and rince off with RO/DI water. Any lye that gets on the surface of the rock will kill whatever's there but after a few months, it'll fill in again.

It's sodium hydroxide and If there's a little left on the rock, it won't harm your tank.

BE VERY CAREFUL NOT TO GET IT ON YOUR SKIN OR IT'LL DISOLVE YOU AS WELL.

Works great for aptasia, Mujano, migrating Green Star Polyps, etc.