What sort of cover should I use?

[Kryos]

Originally Posted by daplatapus

I don't know if it's because of the height of my fixture, or if it's the LED's, or what, but it's a significant drop in light on my tank.

Yea, being a single point light source, LEDs will drop off significatly everywhere in the tank except directly under it because the light is travelling at an angle through the eggcrate and since the eggcrate, as you said, has some depth to it, more gets blocked. Having more than 1 LED cluster will make up for some of it, but you will still see a drop.