Anyway to get a foam wall to stay submerged in a full tank?

[Thalasstronaut]

I should have seen this coming, but I made a foam wall (out of egg crate and great stuff pond foam) to hide some plumbing in my tank. The tank is full and running. I reasoned since I wasn’t trying to seal off the area behind the wall for an ATO, I wouldn’t need to silicone it in place and it would be a sort of cave for fish in addition to hiding the plumbing. Surprise, surprise, it floats. Aggressively.

I’ve searched here on R2R and the two suggestions I’ve seen won’t work for me. I obviously can’t silicone it into place in a wet tank. Even if the silicone would cure underwater, the wall is trying to force its way up the entire time.

The other suggestion I saw was to mount it to slate and bury the tile in the substrate. Problem is I run a RUGF and I’d be blocking the plates with anything I mounted directly to the wall.

I figure I’m out of luck and won’t be able to use it, but I figured I’d ask the community here as a Hail Mary.

Thanks in advance.

 

[malacoda]

The only thing that comes to my mind is weighting it down some how ... with something really heavy. What that something heavy is I don't know. All depends on how thick and stury the foam wall is. Perhaps lash some tiles from HD to the back using zip ties or heavy fishing line secured to the egg crate?

 

[JTP424]

Maybe carve out some space and glue in some magnets? Then use some on the outside too?
You would have to removed it every now and then anyways as I feel the detritus would creep back there and just decay.