Potassium monopersultate in above ground pool with swg?

I need some help calculating the amount of potassium monopersulfate to add to my above ground pool. Its roughly 14,700 gallons and has a salt water generator. Friends of ours have recommended using a non chlorine shock to maintain the free chlorine levels, etc. PMPS was all we could find around our area at any pool store or otherwise. I normally use the pool math calculator but, PMPS is not listed as an option for calculating. I would also like to know what i should expect as far as my other readings after I add it so I can prepare accordingly. Also, will it increase the free chlorine reading? I usually can find a significant amount of info when i do a little homework but quite frankly, i don't feel much like doing the reading. Any advice or info would be much appreciated. Thanks in advance.