if your over flows cant handle the flow then you didnt resurch properly before getting the tank made i have 4 x 50mm drain pipes in my tank and that lets me pump 13,000 gal per hour with a over flow drain in the sump for 24/7 water change
i pump 200 gal per day into the main tank and that fills the tank and when the level gets high in the sump it goes into the main house drain
i run a 6x2x2 sump at about 18 inch full all pumps have non return valves so you dont get back flow if you get a power out
this tank has been set up for over 2 years now with no problems
when i 1st set the tank up i had about 1/4 of the turn over and it wasnt enought
another thing to do is to put 3-4 big air stones in the sump this airs the media
i pump 200 gal per day into the main tank and that fills the tank and when the level gets high in the sump it goes into the main house drain
i run a 6x2x2 sump at about 18 inch full all pumps have non return valves so you dont get back flow if you get a power out
this tank has been set up for over 2 years now with no problems
when i 1st set the tank up i had about 1/4 of the turn over and it wasnt enought
another thing to do is to put 3-4 big air stones in the sump this airs the media