Oil_Fan

That sounds about right. I have 4 pieces of base rock in there. One started converting almost immediately. The others are a bit slower. One is slowly going but the other 2 not yet. It's on one of them that I've started to see it. First it was the diatoms, finally got that under control (too much food) and now this.

I have 2 kinds of snails, nataruis (sp?) and bah...can't remember the name of the other..they like hanging on the glass. Starts with an A. Anyways...I also have 2 emerald crabs.

Gozer_1

Astrea? Good algae eater. You may want to think about a couple more or a Mexican Turbo snail. Ceriths are good for when the algae gets in hard to reach places. They're a little smaller than the Astreas.

Rbacchiega

How long after your diatom outbreak was your tank cycled? I'm just finishing going through it (I hope) with the 90 gallon.