Am replacing seals on a Pentair Whisperflo (2017) and everything was coming apart nicely -- no corrosion etc. I am having a hard time getting the old diffuser-side seal dislodged from the diffuser. I know I need to be careful not to scratch/ding the hard plastic diffuser side so am gently trying to pry the seal out going around with a flat head screwdriver, but it doesn't seem to be budging. Unlike the other half of the seal, I don't think it can be tapped out from the other side. Any suggestions? Thanks! Kate