Regarding shock: I use non-chlorine as I'm using Bromine. However, following the directions which are probably similar to chlorine shock:
o With jets running on high with full air intake, add shock in the amount per instructions. (non-chlor shock is 2 oz, or 1/4 cup)
o Run jets at least 15 minutes. NO ONE in the spa during this time!
o Leave cover open for 2 hours to allow the shock to gas off.
The shock uses oxygen in the water to burn off the dead components after your sanitizer (chlorine/bromine/O3) has killed the little buggars. This is the reason the jets need to be running with as much air induction as possible. Filters can only filter so much of it out where the shock actually removes it.
We find that if the water has any greenish color and cloudiness, doing frequent shocks helps to clear it up. We shock once a week at a minimum anyway, and once the water has been around a while (this is a closed system, after all), shocking more frequently helps clear things up.
We also have the dark blue liquid titled "Spa Klear" but it seems all it does is add more junk to the water.
Experts here on the board will, no doubt, suggest the proper application of Spa Klear where as a rank noob... ('nuf said) B^)
BNMac.