The new home came with a pool that has in floor cleaning system. So far I've replaced the A&A top feed 6 way water valve with an A&A low profile side feed water valve. I also went ahead and replaced all 20 magnasweep pop up heads with the Pentair Gamma 2 heads. I'm noticing some of the heads never retract in the zones in the shallow end of the pool. Seems like water is bypassing the flaps for that zone. Anything I can do to stop the bypass? The other zone pop up heads do come up and go down as they should.