Diy waterfall with viewing area

[crabitatitude]

So many road blocks... I would keep clear of the cardboard. Mostly making it waterproof

[ErikRasmussen]

If it is covered in great stuff isn't it already waterproof? What kind of pump do you use? Did you get water in it yet? Did you seal the whole thing in silicone or is great stuff safe for the crabs?

[Breeezy]

If it is covered in great stuff isn't it already waterproof? What kind of pump do you use? Did you get water in it yet? Did you seal the whole thing in silicone or is great stuff safe for the crabs?

I don't know if Great Stuff is waterproof. Regardless of whether it is or not, crabs will pick at anything made of foam and it will fall apart. When I have seen it used before, it was for fish tank backgrounds, and they sealed it. I'm assuming it might leach something into the water. Better safe than sorry! Silicone sealing will not work for long, based on experience!