I have an FNS Plus 48, installed in March 2013. Recently, it developed a leak where, or very near to, where the top and bottom meet. I am not sure how to best proceed and am hoping for insight. I've replaced the gasket (lubing it liberally), and it still leaks. I've inspected the band clamp and it looks fine, and I can't find any cracks in the top or bottom of the filter. The leak seems to move when I rotate the band clamp. I have tried installing the clamp "upside down" and the leak location still seems to match a point on the clamp. I have been tapping it into place as best I can with a rubber mallet (something I haven't done in 15+ years with no apparent issues) and I am torqueing the bolt until the spring is compressed. I did notice that the bottom swells slightly when I turn on the pump. I am not sure if it had been doing that previously. It is very slight, but noticeable if you look for it. The pressure reads normal and the grids are quite clean (just disassembled and cleaned everything late last week). Is it possible the clamp is the cause of the leak? Should I try replacing it? Or is the apparent correlation with the positioning of the clamp a red herring? If I should get a new clamp, how important is it to get a genuine Pentair vs an aftermarket?