Thanks , I did try that. Used 1/4 tub of jack 37 ( Sorry if I got the name wrong) Did the plugs as well. I even swapped lids with the waterfall pump ( since we never use it ) and no joy. The lid can't be opened when the filter is running or soon after being turned off as the suction is too great. Speaking of suction removing the lid sounds like I'm breaking a solid suction connection ( hope that makes sense ) .