If you still have your glass tops that came with the tank, Throw them out. Get some eggcrate (you will find this at any hardward store, in the lighting section) eggcrate is a white plastic cover for florecent lights, and is plastic strips that make 3/4in squares. cut it to fit the top of your tank. Then use a fan to blow across the top of your tank. Your tank needs to sweat. It is very inportant. Just like people need to sweat to keep cool. And finally don't have your lights right on top of your tank. Try to get at least 4inches between your lights and the top of your tank. You should keep some fresh RO/DI water handy to top off your tank daily. Your water will evaporate. But this is good.