do you have any probs with MHs raising water temp?
that hood will trap lots of heat coming out from MHs if ur fan(s) are not strong enuf.
I have my light 8" above water surface and there's a 5" slid around the light btw the hood and the light. 2 built in fans and still, water temp raises 3 degrees easily. I have to set a big floor fan to blow air to it to keep the water from getting too warm.
the link below is my tank.
https://forums.saltwaterfish.com/t/252748/here-is-my-baby
Oh, and the backer looks like there's water/moisture btw the glass and the backer.
might want to take it out, clean and dry it and attach it back in.
I have better pics when I take pic of the tank w/o flash. Try w/o flash.