[coolclearwater]

Had the same problem with my 20" o ring although mine was visually bigger as if it was an incorrect o ring. I contacted the ebay seller where I bought and he assured me he would rush me a new o ring. I never got it!! But I fixed the problem toot sweet. Soused some plumbers grease (any big box store) on the o ring. Placed the O ring in the filter cap and installed the cap onto the housing with housing turned upside down (you might not have to do this) to insure the o ring did not drop down. Did all this work with the filter housings inside the bathtub (to drain). Well it worked. I was thinking that I would have to buy a o ring kit and make my own new o ring later. Could possible cut a small o ring section out, 45 degree cuts of course and super glue back together. Anyway just to be on the safe side...Placed the filter housings in a retangle plastic tub and as I monitor gages for equal pressure I also check for leaks. Have yet to find one. Mine was also blue housings Black caps but I have two 20 ".