[Myka]

Well, to start off you have too many fish in your tank...especially if they are any decent size yet. As they grow the problem will become more pronounced.

What kind of algae are we talking here? Is it diatoms (brown)? Dinoflagellates (brown and bubbly)? The bacterial cyano (burgundy or black)? Something else?

Algae is caused by excess nutrients (fish food, fish poop, etc) which will result in nitrate and phosphate being at elevated levels. Sometime the algae grows so fast that the water will test "zero" for both NO3 and PO4 though. Regardless of the test results, the cure is still the same - reduce nutrients. The main culprits are overstocking, overfeeding, poor husbandry, poor flow, and mediocre filtration (wrong type or not effective enough). If you could provide more information about the type of powerheads, protein skimmer, and filtration you are using that could help.

Most tanks do best with some sort of sand sifter to keep the sand turned over and clean. I keep a shallow sandbed (<1"). I use a freshwater gravel vacuum cleaner to clean the sand. I also use conches to turn the sand over. For a small tank like yours you could put a small Fighting Conch in there (they don't fight btw). Look for one about 1" long. Your hermit crabs might make a meal of him though, so it would be best to replace the hermits with the conch. You can get sand sifting fish, but most of them make a mess and another fish is the last thing your tank needs.