the best overflow

[duanes]

Any commercially made overflow box should start and stop with a power outage, as long as it is properly installed.

I use several different kinds on my tanks and all hold including a CPR. With the CPR as long as you attach a powerhead to the tube or luft pump to the air release tube, siphon will restart.
My powerhead venturi constanly removes any air build up in the CPR below.

 

[beaumodr]

I've ran an eshopps overflow for 6 years on my reef and it has ran like a champion for me with too many power outages to count. I would be worried to have to rely on powerhead/pump to restart my siphon but thats just IMHO