I bought a new pentair pump about 6+ months ago, and that is about when I noticed my filter system acting differently but it might be a coincidence due to the age of the original equipment (incl the filter housing) which is about 12 years old. What recently happened is I noticed the top of the filter housing leaking off and on - under the pressure gauge and sometimes I've seen a drip between the bottom of the pressure gauge and the top of the pressure gauge. That never happened before. But the pressure gauge is working ok so I didn't replace it - it's not cheap, and most of the time there is no leak. Yesterday I opened the housing to clean my filters and they were stuck in tighter than ever. I could not get the top plastic part off - I had to use a screwdriver to pry the top off all 4 filters (I've never had to do that before.) Once I had that off they were stuck very tightly to the bottom plastic rings also. In the 12+ years I've had the pool this has never happened before. On the last one, I broke the plastic piece that holds the filter at the bottom - it broke off completely stuck in the filter center! So I cleaned the filters and put it back as good as I could and it seems to be in tightly and it's working fine as before, but I wonder why after all these years would the parts be so hard to remove? Has anyone else seen this before? It's a combination of odd things: intermittent leak under/around pressure gauge, new pump, and very tight filter cartridges both at top and bottom of filters. Could this be caused by too much pressure inside the filter housing? Or the pump? Any ideas? Also, I've replaced my filters only once. The original hayward filters were not as tight as the replacements I bought, which are the brand called "pleatco" - they have always been more snug but not so tight I could not get them off by hand, until yesterday!