[trilinearmipmap]

OK I don't want to seem down on these lights but it seems (in addition to previously voiced concerns about irregular refraction at the non-planar air-water interface, light attenuation due to longer path through the water for reflected light compared to light focused by optics, and incomplete reflection from non-pristine interior tank walls) eggcrate would be out of the question considering the wide dispersion angle with no optics. When light is more or less vertically entering the tank eggcrate doesn't seem to have much effect but with the wide spread of light coming from this fixture a large amount of the light would be blocked by the eggcrate.