Hi, I have alot of bubbles exiting the drain line into the sump/fuge which results in bubbles in the display tank. I have a 120 gallon tank with a center overflow, the drain line under the display tank is 1 1/2 pipe, there are two Quietone 6000 return pumps. Just above the return pumps on the return lines are two ball valves and on the 1 1/2" drain line there is a ball valve. If I partially close the drain line ball valve will this eliminate the excess bubbles? If I partially close any of the ball valve will I have a flood or will the pumps be damaged or caused the lines to burst? I purchased this tank used and the excess bubbles seem to be the only problem. I would rather not use filter socks or foam because of the build up of nitrates. Thank You



