I have a 90 gallon tank with a sump pump filter. When I set it up initially, it was working just fine. But, when I went to add the gravel, I removed about 2-3 gallons of water to account for water displacement from the gravel. Ever since I added the gravel, the water level in the sump tank will not maintain a good level. It keeps pumping the water into the tank until it reaches the pump itself, making the tank level a little too high. I have included a rough picture of the drain pipe (can't take a picture while it's in the tank). I never adjust the slide height of the drain pipe while putting the gravel in. Does anyone have any experience with these or suggestions to keep the water level optimal in the tank, but the sump tank at one as well without it constantly dumping the water out into the tank?