Turbosek

Ok, I have everything plumbed and set up on my new 162 gallon in wall tank. I am about to add the substrate. I am concerned about the water line. I have a sumo, so the water line only move up or down if I open or restrict the drain coming from the overflow. I attached the wall wood trim around the tank, filled nail holes, paint, etc, and whe I have the overflow drain fully open, the water line is about 1 inch below the trim. I have to back the drain off about 30% to get the return pump to raise ...