i have a 12gallon setup running with a big chunk of live rock that has lots of purple algae, green hair algae, and even some hairy brown algae growing on it. i recently noticed these hard looking white tubes that have purplish/red feathery worms shooting out of them. the biggest is about a half an inch long and there are several others. what are these things? i can also see a couple of white/clear looking inverts running around under the edge of the rock. theyre about the same size and look almost like transparent beetles of some sort. any idea what these are and what theyre doing for my tank, if anything.