rtk wrote:
I've developed a nasty case of brownies. I think it's just a coincidence
that I opened a new bag of salt, same company. No new anything in the
tank. I tried an inch of fine sand on top of the old, but that didn't
stop anything. I change 6 gallons of water per week from the 55 gallon
tank. Here's a pic with a few details:
http://www.personal.psu.edu/faculty/...l****erID.html

I'd appreciate any suggestions. It is seriously ugly.

rtk

Just add a small conch or two and stop worrying as to the why.

The conch will make short work of diatoms on sand. Problem solved.

If I had to guess as to what is going on... there must be SOME new
source of nutrients that the diatoms are blooming from - you may want to
test your phospate levels, or just try some phosban or other iron
hydroxide based filter media as see if it helps. Could be organic
matter? Is your skimmer clean? What do you have for cleanup crew for the
sand? (I don't see ANYTHING in the way of sand cleaners on the link you
gave) I am thinking that you simply have to much organic matter trapped
in your sand bed. Which is not bad in and of itself...