With your CYA at 90, that means that you have to get your chlorine level up to between 20 and 25 ppm in order to attain shock level that will kill off the algae. 4 1/2 gallons of 6% bleach would do it, but you need to test and add more bleach as often as you can to maintain that 20-25 ppm level until the pool is cleared up. In your pool, each quart of bleach will raise your Cl by approximately 1 ppm, so you can use that as a guide to figure out how much you need to add each time. It is consistently holding your pool at shock level that will kill the algae off, and running the filter 24/7 that will help remove it from the pool. You will need to keep an eye on your filter pressure, and clean the filter as it indicates. Brushing the pool daily during this process helps, too.

I would not use anymore stabilized chlorine in your pool--no more trichlor pucks or dichlor powder, because your CYA is already very high, and that's going to mean keeping higher base levels of chlorine in the pool to keep it from turning green. Plain, unscented bleach will do the trick, but first you need to get it up to that shock level and hold it there until the algae clears up.

Janet