I can tell you this. Many inground pools have a chlorine treatment system. HTH is the brand of chemicals usually sold to put in a treatment system like this. They are big blue pills you put into a filter/recirculation pump and storage tank.
This tank is usually in a heated environment to protect it from freezing in winter. (like your garage).
The HTH pills are essentially CHLORINE TABLETS. The pool is supposed to be checked for Chlorine content and PH balance. I suppose you could even use Chlorox Bleach instead of HTH tablets.
You would have a odor of chlorine in your garage NO MATTER WHAT.
Some people and public pools keep Chlorox bleach near the pool with a foot sized pan for each person to step into before entering the pool. THIS IS TO CUT DOWN ON TRANSMITTAL OF ATHLETE'S FOOT to OTHERS ! ! ! ! ! ! !
I thought I'd check in after I got done with my emails.. We just bought an above ground pool last summer...it's pretty large. Takes 3-4 chlorine tablets at time..we expect to use more this year cuz of our kids friends coming over. but they are normally stored in a sealed container. Our tablets are sealed in a plastic wrapper individually..and then stored in a plastic bucket. I agree that they have an odor..I would never mistake them for bleach smell.. whew!!!