Dryn

What can you use to cover up spray-foam when using it to divide a water feature in a palladarium? I'm using styrofoam board with very large rocks up against it sealed with "waterfall" expanding spray-foam. I don't like the look of the spray-foam between my "boulders." On the background part, I covered the foam with coconut fiber and substrate mix. Can I use the same thing underwater, or will it decompose? Can I use the substrate from the water feature (eco-complete)?

MATTHEW MAHLING

You can use the cocos fiber but, it will be messy.
Trim the foam around the stones if needed. Place a layer of ge silicon II (black, brown, tan are good) on top the foam, then immediately press eco complete, sand or gravel on top of that. I usually dump a bunch then pat, pat, pat. Works great with super coverage.

Sphearion

I would not use GE silicone II as it has a mold inhibitor in it that can kill fish makes me a bit leary of what it could do to other things in the tank as well. I tend to stick with the original GE Silicone I without the mold inhibitor.

Dryn

FIY, I called and talked to a rep from GE and he said that their black silicone formula didn't change when they added the mold inhibitor disclaimer on the labels. The old silicone still has the same mild inhibitors in it.

MonopolyBag

Don't use one. In all of my tropical terrariums with water I just don't use one, instead I make a water table, and use other techniques to work around having to use one.

maverick3x6

aquarium grade silicone is always an option as well