If you didn't say that the reactor would be submersed, I'd be telling you to avoid trying. Silicone is pvc safe, but probably not the best idea. PVC cement actually welds the pieces together. Give it a try and tell us how it works for you.
Aquascape? I'm a crypt farmer.
It's a fine line between fishing and standing on the shore looking like an idiot.
That IS an aquascape, it's titled "The Vacant Lot".