Eggcrate easily. Its thicker and it directs the light only downward through the holes.

i was thinking to extend the height of my tank about 4 inches with eggcrate, that would hopefully stop mos fish jumping out, and not block any light?

has anyone tryed that before

You might have more success with the reflective eggcrate, but I'm not sure if it will heat up, or have a reaction to the salt water.