Last night I adjusted a powerhead to hit the front of the glass, and apparantly overnight and while i was at school today the current flowing down the front of the glass pused the sand around alot. Well i went to push it back up against the front of the glass, and when i did, this nasy milky brown junk came from the sand. I've seen it before when the sand got stirred around but never really thought about it til now. Is this normal, or do i have too much waste in my tank or something like that. Any help would be great! Thanks!