1. Maintain chlorine levels.
2. Lower your pH to 74 - 7.6
3. Get some stabilizer in your pool.

Do you have access to a nearby Sams Club? If so, go buy their PoolBrand bags of dichlor shock. Using dichlor will add BOTH chlorine and stabilizer . . . and you need both. It will also tend to lower pH and ultimately, alkalinity, and you need that, too.

If you don't have access to Sams, you should EITHER

+ Buy this dichlor from Amazon:
Kem-Tek Dichlor 22 lbs
*OR*

+ Shop around for 15 - 25 lbs locally . . . BUT YOU HAVE TO BE A CHEMICAL LABEL INSPECTOR, to make sure you are NOT getting the blended and diluted goop that Walmart, Costco and most others are selling. Some of it has fairly harmless stuff that allows them to offer "enhanced" shock that's cheaper to make but they can sell for more, but some of it adds copper to your pool!

By the way, if you order form Amazon, you can get the Amazon free Prime trial:
Amazon Prime
and get free 2-day shipping for a month. But, if you don't want to keep it, REMEMBER TO CANCEL IT before the month is up. Personally, I'm a late shopper, so it saves me a bundle at Xmas.