what is the best way to set up a fuge underneath my stand on a tank that is not drilled, and how to keep water from overflowing out of the fuge when the power goes out?
To help stop overflow I drilled a small hole just below the water on my return lines in the display tank and this breaks the syphone in case the pump stops.
I used a HOB overflow which limits the amount of water that can flow to the fuge while still maintaining syphon. I put a diagram in the my dyi refuge thread
I did the same thing as beaslbob, and it worked fine to keep from flooding my dining room. The trouble you will come across so far with me is maintain a constant water level in your fuge. I'm working through that right now.
