My test Numbers:
FC 1ppm
PH 7.5
TA 130
CYA 40

My pool is only open for the summer I close it in September and re-open in June.
This year I started with the cartridge that I put in last august and that will most likely last till this august.
So i replace them every 5 months of use.
It works for me as Im using less chlorine than i hear some people using.
Their website says that nothing effects the life of the cartridge, so I cant see an issue with removing it at the end of the season and re-using it in the the spring.


Above ground pool 6600 gallons
Hayward super pump
Hayward EC50 DE filter