As we suggested above, with a cya of 0, you need to be shocking the pool up to 10ppm. What was your cl reading before you added the 3 quarts last night? Try testing in the morning before work, as soon as you get home from work and then as late as you can before going to bed and each time, add enough bleach to get back to 10ppm. I know it is difficult, but it is crucial to sustain the shock level. If you let it yo-yo up and down, you'll never clear the pool. In a pool your size, each quart of 6% bleach should add about 2.5 ppm of chlorine.