DBD,
IMO I wouldn't run a tank without a top, they protect debris and stuff from magically falling into the tank and also for keeping the jumpers under water
I have been using a 1/2 sheet of acrylic over my tank now for almost 7 years and things are growing great. The trick is to keep it clean, which I give it a rinse in the shower about once a week. I have three 2" holes drilled for feeding, gas exchange and also for my return lines.
Did I mention that I'm only running NO's
