Last fall I discovered something that I can't believe I didn't figure out sooner. I took a piece of foam board insulation and cut it to fit the top of my tat then cut holes in it for the lights. It's soooooo easy and takes care of a 9 year stress issue for regulating heat and humidity. I hope this helps someone in here, it has been great for me!!
That sounds like a great idea. The foam wasn't affected by the heat of the lights? Where did you buy the foam?
I asked my mom about using a large piece of Styrofoam but she said it may have bad chemicals for the crabs or something. Plexiglas is also great.
I did the foam board thing. I have an approx. 20g plexiglass tank and nothing really fits the top so i used your foam idea. It just rests on top, and i jabbed some holes in it. The crabs can't get to it, so not too worried about them ingesting any bad chemicals. Thanks for the idea. You're right. Solves a lot of the heat and humidity problems.