 Re: power out filter overflow.....
That's hard to answer without seeing what yours looks like (sounds like what Jason said) Your overflow should be set up so that when the power goes out it will syphon until your tank goes down to a certain level and stops without breaking the syphon. Your sump or wet/dry should be set up so that it can handle this extra volume of water until the power comes back on. The return line from the pump to the tank should have a check valve in line so it will not back flow and overflow your sump. Understand??
Jim
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90 Gallon glass, 135#'s of rock and 2" sand. 2-250w 20k XM metal halides. 2-95 watt actinic VHO, 4 powerheads, Coralife skimmer. Maroon Gold Striped Clown, Blue Chromis, Kole Tang, Pygmy Angel, Serpent Star, Brittle Star,Gorgonians, Mushrooms, Yellow Polyps, Turbo Snails & Blue Legged Hermits. 20 gal sump with Caulerpa, Mag 7 return pump. | 
