Try again. Need to build a sump out of a 180 gallon tank by the week-end. Using equipment that I have on hand except glass for baffles. the mars filter is a pull from a cracked tank and has an overflow built into it. this will determine the height of my waterline. Need to know how much space I can get away with for the middle section and still have a safe amount of water for the sump area. Don't want to have to fill up this section too high as I will have 4 large tanks draining into it. 880 gallons. Can i use plants in the middle section even with flow and air going into it. Thank you for any constructive input.