Sound like a species of sponge (Class Porifera) (fuzzy little
volcanoes), without seeing it that's what it sounds like, I have seen
them grow in dark out of the way places. The older your tank becomes
the more you will eventually see, In one of my tanks in just over a two
year period I had approximately eight different species of sponge show
up. They are great for your tank and aid in the filtration of water.
Chris Carney
www.exotic-aquatics.com

Kelly wrote:

I moved around some rock yesterday and found two different white things.

1) They look like fuzzy little volcanoes, really small cones with a hole in
the center. There was one that was bigger it appears they grow wider around
the base as they get larger, they have the look of cotton.

2) Appears to be white Coralline but I have never seen that before, does it
exist? There are specks on the glass in the back of the tank that feel like
coralline and don't come off too easily. I also found the same white stuff
growing on one of the rocks back there.

Since adding my power compacts I have noticed a LOT more growth over the
last two weeks on the rock and some of the stuff I just can't find on the
net.