I just installed a new Pentair Clean and Clear 150 to replace my 100. I cannot, even with an assistant, get the top to seat on the housing. We can get it on about 3/4 but then it will slip off on another side. Lots of lube, even tried reusing the o ring from the previous filter. I would appreciate any tricks that will get this top on this filter so I can get back to relaxing. TYIA. BTW, I know it will go on because it was fully seated when I took it out of the box.