If your CYA is at 80, then you need to bring your chlorine level up to 20 ppm and hold it there by testing/adding more chlorine as necessary to maintain that high level. You need to hold it there until the green clears up, and you can go from one night to the next morning without losing any chlorine. Pump and filter need to be running 24/7, cleaning the filter as the pressure indicates, and the pool needs to be brushed daily, preferably right after a chlorine addition. You're going to need FAS-DPD testing for this--if you'll take a look at the testkit link in my sig, the K-1515 is the only standalone test you would need to make your kit a true FAS-DPD kit and would make this a much easier project for you.