Dude, you just need a clean up crew. Diatoms are a common in a newly cycling tank. Where did you get your sand? Is it aragonite based? You can tell if you take a pinch of it and stick it in a cap of vinegar. If it's arag based, it'll fizz. The best rule of thumb in my opinion is to go to the fish store, look at the fish, and buy as many hermits and snails as you can afford instead. Do this several times! Blue legs are the only real recommended hermits, but I don't mind the reds either. Nassarius snails are awesome, ceriths, turbos, astreas, and nerites are also great for diversity. Even though they're cannibalistic, bumble be snails are cool too. I have had all of these in every tank I have owned, and they're not as bad as alot of people make them out to be. Snails don't eat live fish, but it one is dead or right at the point of death, count on them to clean it up!