This is a good start, but you're not going quite high enough with the chlorine to actually burn off the demand. You need to get to 20-25 ppm, since your CYA is so high. Since each gallon raises Cl by 3 ppm, that means you need 7-8 gallons in at first, then to add more at dark and in the morning to get back up to the 20-25 ppm. It will go faster if you can also test and re-add 2 or 3 times during the day.

Since your CYA is so high, you really need to consider draining and refilling about 1/2 your water, because even when you get the chlorine demand worked out, you're still going to have to maintain 8-15 ppm Cl at all times to keep the algae away.


Janet