I calculated the back-flow volume coming back from my DT and then calculated the maximum height as well as location of ATO floats (water height in the return section of the sump). When people look at my sump they tell me it will overflow, but it doesn't even come close.
I wanted high baffles to maximize water volume and wanted all my flow-back water to fit into my return section. So baffles were made about 1 inch short of the top trim. Please do the calculations to make sure you can use high baffles....since your flow-back might be totally different than what I found.
Here's the specifics.....
1. Calculating volume of drain-back when pumps are off. I made the assumption that my tank maximum height would be halfway up the saw-teeth on the overflow.....about 1/2 inch. With the interior dimension of the tank 59 x 17 inches, that comes to 501.5 cubic inches of water coming back into the sump. If you want you can covert this to gallons, but there is really no need to do that because you simply work with cubic inches in your sump. (FYI, 500 cubic inches is 2.16 gallons)
2. Calculate how much room you need in your sump: My return section is 17.5 x 10.25.....so how far down do I need to set my ATO (water height in the return section)......
17.5 x 10.25 x A = 501.5
A = 2.8 inches
Here's my sump (the black line (water level) is about 2.8 inches down from the baffle height)
:
I was off by a touch....the water comes maybe 1/16 inch over the top of the baffles....but still plenty of room to spare.
Hope this helps.
