1. Do a dilution test with the CYA, to determine your actual level. Mix 1/2 cup tap water (or distilled) with 1/2 cup pool water, and run the CYA test against that mixture. Multiply the result x2.

2. If you actually already have 40 ppm of borates (how did you test?) go ahead and take the level up to the 60 ppm effective level. On your pool, that would mean about 7 more boxes of borax and about 2 gallons of muriatic acid.

3. Your PF (PoolFactor) is about 6. A gallon of 8.25% bleach contains about 0.7 lbs of chlorine. So, each gallon will add about 6 x 0.7 or 4 ppm of chlorine to your pool. Three gallons will add 12 ppm. That will get you to 20 ppm. Get there, and keep it there for awhile.

4. Get a cheap OTO (yellow / red drops) kit locally. Use it the next time your test your pool. It will turn very dark yellow to orange --learn to use it to get a guesstimate of your high chlorine level, without using the DPD - FAS test every time.

5. Brush your pool at least 3x per week, each time AFTER dosing with chlorine.

6. Try all that for a week. If you don't see an improvement, add another 4 boxes of borax, another gallon of acid, and take your chlorine levels up to 30 ppm.

You CAN swim at FC=30 ppm when CYA > 100 ppm, with no ill effects on people. We're not quite sure what those levels do to women's fashion swimwear, so leave the $120 swimsuits in the house. . . unless they are old.