Sounds like not enough random flow in the tank to keep the grot suspended. Might try moving some powerheads around, or moving your returns.

The other thing you can do is use a turkey baster to blow the rocks off just before you do a water change, that helps get the nasties out too.

Don't worry about your feeding schedule, I also feed every other day, my fish are fat and happy. If your fish are in good health, and you are already fighting algae and detritus buildup, the last thing you want to do is add more problems by feeding heavier. What do you feed your fish? It's been my experience that flakes and pellets seem to cause more algae issues and trash buildup than frozen.

Tell us more about your tank and it's inhabitants, then maybe someone can offer more extensive advise. Be sure to include your latest water parameters, and what filtration you are using (sump, canister, etc).