The easiest way is probably to use dichlor. On your pool, 1 pound -- a little more than 1 cup -- will add about 2.5 ppm of chlorine, a little more than 2 ppm of stabilizer, and lower the pH.

The best source is the 50lb containers of PoolBrand dichlor, sold at Sams Club,or the 24lb box of PoolBrand dichlor shock. Most other retailers, including Costco and Walmart, are selling 'voodoo' blends of dichlor that may contain borax, magnesium sulfate, aluminum sulfate, copper sulfate . . . or anything else they can think of to mix in.

If you don't have access to Sams, the Kem-Tek dichlor sold on Amazon is unblended:
Kem-Tek Dichlor 22 lbs
If you buy from Amazon, you may want to get the Amazon Prime service, which means any package sold by Amazon (NOT: 3rd party sellers!) will ship 2-day for free, with no minimum purchase or weight. There's a 1 month free trial, so you can cancel if it's not worth it to you. (If you are like me, and a late Xmas shopper, it's a life-saver!)
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