hey guys I have a problem with my new herbie drain. The water level in my overflow keeps fluctuating. No matter what I do it goes up and down at first I thought it was because my vortech mp40 was pushing to much water but I was wrong. The way it's plumbed is one 1" main full siphion drain and one 1" emergency, gate valve on the full siphion. The return pump is a vectra m1 calibrated to my tank. I tried the return turned all the way up and all the way down to see if it was pushing to much but nothing mattered. The tank is a marineland reef ready with a corner overflow. Any help would be great!! Thanks