coolEgg crate is sold as lighting diffusers for dropped ceilings at home supply stores. A4'x2' section is around $12 or so.
The sooner you put it in the better. IME the back lighting really helped. on smaller tank you could just use spiral pig tail screw in fluorescent blubs designed to replace incandescent. With round clip on reflectors.
On my 4' 55g the 4' 2 tube shop lights work nicely.
my .02
It must be acclimating to the water, its moving around alot more than it did the first day or 2. It was missing most of the day yesterday, and last eve before i went to work it was out on the rock. Now when i got home this morning the pellet looked like its moved under the rock to a place where it doesn't look like it could have rolled to, and the crab is missing again.Lol well it moved so it was alive
i will give that a try tonight. Do they leave their rocks to feed?Yes, it's their job to clean up any uneaten food. Once it's been taken care of they go back to hiding.
Try dropping a pellet in at midnight and come back to look 5 minutes later to see what has come out to feed.
If the food is not in reach they often leave the rock. Look for Mysid Shrimp and Amphipods too. Probably Copepods as well. Copepods have one eye that shines back from the flashlight.i will give that a try tonight. Do they leave their rocks to feed?