foamboard as background for aquarium

Concrete is porous, meaning not waterproof. If the bg gets wet without being sealed, it will wet the paper and it will likely peel or at least break down. It's risky move, but it may or may not work. You could try to remove the paper leaving only the foam behind. I suspect this would be pretty hard to do.
Have you looked at a home improvement store for styrofoam insulation sheets designed for garage door panels? That's what I am using. They are about half an inch thick, which isn't that thick. They don't have the plastic or foil backing either. That's what I would suggest. 1/4" difference isn't worth the headache IMO


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Zorro, I imagine you can coat anything and have it aquarium safe. If I wanted to coat clay bricks, for example. Clay can contaminate water unless it is coated. What do you coat your background with when you are finished?

I'm using styrofoam and concrete only. I don't plan on coating mine. I want mine to stay porous so it is more rock like.


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