Like this kind:
https://www.youtube.com/watch?v=7DFk4bnIxEg
Just wondering who has been running these for a while, and any problems with failure of the overflow / floods etc.
The design looks pretty well foolproof and I was looking at a couple of redundant failsafe systems: float switch to cut the return pump, run tubing to venturi on return pump to keep the overflow primed, and water detector / alarm. Also I would run it as a trial in my basement for a while to test it out.
Interested in real life experiences with these. I have a 30 g cube up and running, I am not going to drill it.