Sump help

[hillegom]

You will have to use aquarium safe silicone, after all, your aquarium water will end up going through there.
If you are only trying out the sump without tank water, then IF you remove ALL traces of silicone then it will be ok. But for how much, 2-3 $ it would cost extra for aquarium safe silicone, do you want to chance it?

Its easy to remove silicone from plastic, you do not want to use any remover, might melt the acrylic.