I also live in Leander and have a 13,000 gallon pool that was installed in May. I add 40-50 ounces of 10% bleach (Lowes) every morning (less when I have the 12% from Leslie's) to go from an FC of 4.5-5 to 6.5 - 7.0. My CYA is 40. That would equate to about 70 ounces per day for a 20,000...