I have a 20,000 gallon SWG pool. Combined Chlorine 4ppm, no FC. I Shocked with 10 pounds of granular chlorine CC the next day was .9ppm. Shocked the next night with 5 gallons liquid shock still no FC. Should I consider non-chlorine oxidizing shock just to rid the pool of the chloramines? The pool is 95% clear.
– It sounds similar to challenges we’re having with a few pools to get them to establish freechlorine -this winter seemed hard on the pools/water chemistry wise.
I would shock the pool with 20x the normal dose of chlorine to break the lock the total chlorine has. So for a 20k gallon pool 2 cases of liquid or even 3 may be necessary if you are not seeing it change. The non chlorine shock would not reset the free/total chlorine – so super shocking is in order. We find that liquid does the job better than granular on pools we service.
Do you know what your stabilizer level is? Make sure it is at about 30 when you get the FAC chlorine level to start registering.
Test strips also have expiration dates, so be sure to replenish your supply for the season and check that the dates are current.