IM 75 ext repair

[noobsalt]

Hello, I am a little over a year into the hobby and just bought a used IM Nuvo 75 EXT (a nice upgrade from my 30g glass box). I am in the process of cleaning it and noticed that the back wall is separating from the glass a bit. I don't think it matters, functionally, but I'm not in a rush to set it up and want it to be done right. I don't want snails or something making their way down there. The external overflow box is fine. It is separating at the top but also below the overflow. What would be the best thing to use to "glue" this back into place and keep it there? Gorilla glue?

I've attached a pdf photo that hopefully goes through.

Thanks for any advice! Long time lurker.

 

[SnowyFox]

If anything, I would try some aquarium safe silicone. It is also used to attach acrylic overflows inside of a tank as well. I wouldn't use something like Gorilla glue personally, as it likely isn't very safe for fish