Explosion of feather dusters? Cotton? Help?

[mcgruff]

I bought some new LR about a year ago and now have thousands of small white (looks like feather dusters) in my sump. Most that set up shop in the tank have been consumed by the fish. I am curious as to what these "things" are. They currently avg. about 1.2cm's. Should they be cleared out of the sump (they're everywhere, heaters, skimmer, pumps, etc.). Compounding the issue is some mold that's started inside the sump above the water line that I'd like to remove. If that's not enough, I've noticed some beige cotton looking material in my pr-filter and in the sump. To be honest I don't know if this means that my system is maturing or going into the tank (so to speak). I would be curious to know what the experts think.
Thanks!

 

[surfnturf]

I have had these animals in my tank as well. They apparently are a tube worm and are harmless. In my tank, they multiplied like crazy and I thought they would overtake the tank. They seemed to reach a certain population, then started to disappear. I still have about 50 of them, but I'm not worried about them. They are a filter feeder and as far as I'm concerned they are helping keep the tank clean. They never seem to get any bigger than the size you described, and I've never been able to find pictures of them on the net. Hope this helps a little. BTW, the beige cottony stuff, this is only a guess, but it may be a sponge.

 

[drkegel]

Probably barnacles - and pretty much harmless. They are filter feeders, and IME, they reproduce very quickly.

 

[ocellaris_keeper]

This is a very good thing, it means your tank is building it's own ecosystem, fresh with real ocean animals brought in with your tank.
These filter feeders will do thier best to keep your water clean of nutrients too.
Congrats!

 

[surfnturf]

McGruff, you want to see what is actually in your tank, wait until the tank has been dark for a few hours, then sneak up on it with a flashlight. You'll see snails, worms, pods, all kinds of stuff you never knew were in there. It's all good stuff, you've got a thriving ecosystem, as ocellaris_keeper mentioned before. Things are always in flux, things like the tubeworms will seem like they are going to take over the tank, then all of a sudden they will diminish to a smaller number. In time everything will reach equilibrium, no worries! BTW make sure the blinds are closed when you're stalking the tank with a flashlight, neighbors generally don't understand these things