I have a 10,000K, 28-watt coralife aqualight (I think that's the right name; it's at home) over my 10 gallon tank and the light is on legs. Looks futuristic. I have a store-bought, two-piece, 20"-long, about 8"-wide glass cover that covers about 4/5 of the tank, but I have also a HOB filter, so the lack of complete glass coverage is okay. I think the cover does hold in some heat from the heater and any generated from the light, and that's okay since it's winter. When spring gets here and the ambient temperature rises (and I don't use the room heater as much if at all), I'll probably remove the cover. After all, I don't have any jumping fish and I like the idea of having a better view of the fish and plants because the cover collects moisture, is a bit dirty (water stains), and it reflects the light, all making viewing more difficult. Finally, humidity added to our dry New Mexico air is always a plus.