Green Fog in Pool - new user/never posted anywhere....

I think you need to get your Free Chlorine level up to 20ppm and keep it there, given a CYA (Cyanuric Acid) level of 75ppm.
I would not use floaters, any kind of chlorine tablets or chlorine powder at all. Your CYA is high and your Calcium, while in the safe range, is toward the high end. Your best bet is bleach or liquid chlorine. I'm guessing your pool is 35,000 to 40,000 gallons (40'*16'*8'= 5120 cubic feet. 7.48 gal/cubic foot = 38297.6 gallons). You'll need 12 or 13 gallons of 6% bleach to get there, or about 6 gallons of 12.5% liquid chlorine. Then you have to keep it at that level, testing and adding 2 to 3 times a day until it's clear.

But if you don't do it your pool won't clear.

(if you figure 40,000 gallons, it takes 4 gallons of 6% to raise your FC by 6ppm)

Carld

Follow Carl's advice and get your chlorine up to shock level (20 ppm for CYA that high) and hold it there until it clears up, as he said. However, once you get it cleared up and clean again, with your CYA that high, you need to not let your chlorine EVER get below 5 ppm, and I would keep it up closer to 7, just to give yourself some wiggle room. If you let it go below the 5 ppm, you're inviting the algae in....

I would also stop using the pucks in the floater--they are continuing to raise your CYA level, and you're going to have to keep upping your chlorine levels to compensate, if you want your pool to stay clear......

Janet

You'll notice that Janet's advice complements mine and others.