I installed a Nature2 Express according to the recommendation from Leslie's, and that recommendation was to put the Nature2 as the last device before the return valve. That places it after the chlorine feeder, and I'm now not sure that recommendation was right. I'm happy with the system and my reduced chlorine usage, but the bottom of the cartridge literally disintegrated after about 4 months and the little balls inside flowed out and into my pool. I wonder if that's from the high chlorine levels corroding the plastic.
I also noticed when I removed the cartridge one time that the insides were all gunked up, seemingly from the high chlorine concentration flowing through it.
Is my feeder just in the wrong place on the plumbing?