My Hayward 22" (250#) runs at 16 PSI with the skimmer and 14 PSI using the Navigator when clean. The Navigator stops working around 22 PSI. I always find that the Navigator causes the filter to get dirty much faster than the skimmer even when the pool looks clean and I run it under the solar cover most of the time. Did you initially run the filter in the backwash position? Hayward recommends you initially backwash for the first two minutes to flush any impurities and fine sand particles. Also are you rinsing after the backwash? This prevents flushed dirt from going back into the filter and pool.