I am working on making Styrofoam islands for crabs I am planning on getting for Puffer food. I so far only have the shape in I wanted to add sand on the top (since i have extra from filling the dank) but I wasnt sure what I could use? The foam I am using is actually non-toxic florist foam and it is very porous, but I only wanted it on the top and sides and leave the bottom bare for safety sake.
So any ideas? I have a tube of silicone, though its black, I was thinking I could spread that on them thinly and dust sand on? I double checked the packaging and it is indeed safe for aquariums