[Kensn]

I use an Aqulifter to supply my calcium reactor and have found it to be a reliable pump. If you maintain the pump with periodic cleanings, it should perform fine, I think it would be unlikely that the pump would fail and there would be enough air trapped in the overflow to stop it before you noticed.

Your idea seems valid, the little ys you can get in a kit of airline fittings at most any pet store that handles aquarium stuff.