In my oppinion the main problem with having a glass top is heat. Having a glass top traps alot of heat in your tank. About 4 degrees in my case, and i only run normal output florucent lights. If you have a sump that wouldnt be as big an issue, but with out a sump i be willing to bet that you will have some heat issues. Also glass filters the light to some extent, and any saltcreep that forms on the glass would block light. I ditched my glass top for eggcrate. I have to top off more, but atleast my tank its running at 85-86 degrees anymore.