55ga sump help

[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.