Macscale
Aquarium Advice Addict
I would recommend this one and very reliable. You can then apply your idea of making sure none of the tanks will overflow when power is lost. I have ato controller in my DT to stop the pump from overflowing when HOB overflow is clogged up. I have it in my 60 gal tank and i never had a problem.
CPR CS Overflow Boxes
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Seems pretty bullet proof to me. Did you link the correct size or was that just in general?