yeah bigjim that is kind of what I was thinking of doing, however I was going to put an overflow in the sump, and just make sure that the water levels are full, then I would fill the overflow in the main tank, and turn the pump on at the same time, that way it would be a continuous circuit and if the power goes out I would only have the amount of water the is in each of the pipes going into the main tank, which I would be able to deal with. I also had another idea, kind of along cabezon's idea, which would involve putting the refugium at close to the same level or to the side. The only thing is I don't want to use an hob
overflow, and I can't drill the tank, but I don't mind putting the pump in the main tank, as I had already planned on this. Can anybody think of anyway that this would work? I just don't trust the hob
overflows because if the siphon breaks it is a very expensive desk that would be ruined, I could put an overflow in the sump as this is on the floor, beside the desk so no worries about wrecking the desk. Anyways thanks everybody for the help, I know that I am being very picky, I just had an idea that I wanted to try, anyways let me know what you guys think. Thanks so much!