When I get bored, I look at aquarium videos on YouTube.com. I have noticed that there are two types of sand beds... really really nasty ones and pristine ones.

Here is an example of a pristine one that seems to be in a well established tank:

http://www.youtube.com/watch?v=4pl82HUpUtU

I would love it if my sand bed was that clean looking. Mine gets diatom algae on the top. My lawnmower blenny and yellow eye kole tang eat it, but its not the prettiest thing in the tank. To be honest, it makes me a bit nervous when my sand bed has stuff growing on it.

The flow in my tank is good. I do not have any stagnate areas.

Water Parameters:

pH: 8.0
KH: 9.0
Nitrate: ~20 ppm
Nitrite: 0 ppm
Ammonia: 0 ppm

My tank is a 90 gallon tank. I have the tank under a 36 inch T5 fixture with 6 bulbs, 3 are actinic, 3 are 10k.

I have a couple of fighting conchs and about 15 or 20 nassarius snails. None of my corals or fish seem sick. I've got a marine betta that has a roughed up "lucky fin" but it doesn't seem to be bothering him.