Dirty Sand Bed

I'd look at lack of water motion and internal water circulation myself.. The snails will help but they usually only come up for first hand meaty foods not so much for seconds What do you use for water movement and is it a sump system ? Might want to cut back feedings as all that goes in stays in..

 

Er its pretty messy now

HI,
I went with layers of different types of sand , and utilize alot of water movement , my sand is pretty grainy sugar like but dosen't move when the filters run .
I also have a DSB sump that seems to skim all the nasty stuff to it and a bunch of those nassiurs snail are constanly waiting around the return hose for food a semi-circle of feeding snail they don't go near the skimmer or the return pump they hang at tube waiting for the food thats not consumed and other nasties that may trickle down to them. they all hang on the lefts side of the dsb. sump . its kind of funny all 50 of them...
You will need to siphon out the fouled debri first or your bacteria is going to shoot off the scale leading to another cycle . rememeber not all snail eat fish pop each snail has a favorite food some only eat live algae of a certian type, I ve even seen a conch eat a smaller snail yikes ... I use detri eating snails in the sump for debri and a skimmer in the sump for dissolved organic this seems to work and then increas the water flow in the tank, Maybe you could cover that silky sand with a layer of that fine crush shell they import from fla I bought some that was live it was pricy but it really stabilize the sand allthough it may not be worm friendly.
I was over feeding flake and this fowled my tank pretty fast the experts tell me frozen is better if you pre rinse the fish will eat it all in 3 mins or your over feeding, I don't reccomend that brine shrimp exclusivly I hear its not as good as some of the formula foods I try to feed green one day those myosis the next and maybe squid every once in a while.
My tank is clearer and the skimmer seems to handle the organic better.
My 2 cents