I have no idea what is going on here. I've had my overflow box for about a year and lately i've seen the water level get higher and higher to the point where its right on the rim. I've shut the return pump thinking i may have a flood. I've tried to clean the sponge and restart the siphon. I belive the u-tube is 1 inch and my return pump is 600 gph. Anyone have any ideas?