55ga sump help

[tuck]

Hi Everyone

I finally got tired of looking at all the HOB stuff I have on my 55ga. I'm going to build myself a sump. I want to put my protein skimmer, 2 little fishes reactor with carbon and heater in it and have a refug. The actual building/assembly is not a problem but determining the size of sump and the size of pump to return water to the tank is cause for further research. I plan on using a CPR overflow (the small one, for up to 60ga). I believe it's rated at 300gph. I know the sump has to be large enough to hold the excess water from the tank in case of a power outage but exactly how do I figure that out? I would prefer not to use trial and error - that could get messy.

I'd appreciate any help, experience. Thanks

[intarsiabox]

Measure from the top of your normal water level in the display tank to how far down the overflow goes to break the siphon this gives you the height in the following formula. LxWxH in inches divided by 231 gives the volume in gallons. Now determine your normal operating height in your sump and do the same calculation for the volume left in your sump that is above the waters surface, this volume must be greater than the volume you calculated in the display tank.