1 Gal. Res Care Liquid Resin Cleaning Solution

This will help clean dormant resin but would not be a substitute for a sanitizer like bleach. I'd recommend running a regen cycle with a dilute bleach solution first, ideally suspending the regen and letting the bleach solution soak for 1-2 hours, then complete the cycle. Then, run a cycle or two with a heavy salt solution (e.g. 15 lb. of salt in 5 gallons of water that has sat long enough to let some of the salt dissolve into the solution) along with the Res Care liquid. As long as the resin has not been damaged from freezing or other circumstances and the timer/valve controls are working, you should be fine.

As long as your resin is good (not broken down), the regeneration process cleans your resin. Products like these are money pits to mislead users that don't understand that if you have good resin, it will clean itself. If you don't, time to rebed your tank with new resin. High amounts of chlorine or chloramines in your incoming water source can deplete your resin media. If this happens, there is no amount of cleaners that will rejuvenate your media to where it will function as it supposed to.

Neither. It cleans the resin thus allowing your water softener to operate as designed. If the resin balls are not stripped of salt buildup over time, your softener will not soften the water.

Yes, it is for cleaning white resin chairs.