Yes, we're advising you to add enough bleach to raise your FC from whatever it is now to 20 ppm. In 13,500 gallons of water, each gallon of 6% bleach you add will raise your FC by approximately 4.4 ppm, so you can use that as a guide to figure out how much you need to add. You need to reach that level, and then hold it there as consistently as possible, which will mean testing and adding more bleach as often as you can during the day, until you are losing less than 1 ppm of chlorine when testing at night and again in the morning before the sun hits the pool (to rule out UV consumption) and until your CC gets to 0.5 or less.
Once you've reached that point, you can let your FC drift back down, but with a CYA of 90, you'll need to always keep it in the 8-12 ppm range to keep the algae away.
I use WalMart's generic ultra bleach in my pool--it is 6% the cheapest I can find it around here anywhere...
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