How the math works
Chlority mathTarget rating = your gallons × 1.25 for normal use, or × 1.5 in a hot climate, with heavy bather loads or full sun. Systems and replacement cells are listed when their maker-rated pool size is at least your volume, and marked when they also reach the target.
LimitsRatings are each maker's maximum pool size. A replacement cell must also match your control board; check the model on your existing cell or the maker's compatibility list.
Questions
Why oversize a salt chlorinator?
A larger cell makes the same chlorine at a lower output setting, which reduces wear and leaves capacity for hot, busy weeks. Salt cells typically last about 3 to 7 years.
Can I use a 40,000-gallon cell on a 15,000-gallon pool?
Yes, as long as it matches your control board; you simply run it at a lower percentage.