Yep! It's there. Sometimes we forget that we have already asked somebody to fill it out with all the people we help each day!

With a CYA of 80, you need to be keeping your FC between 5-10 all the time. Losing 2-3ppm of FC in a day is very normal. In a 23,000 gallon pool, each gallon of 6% bleach will add about 2.5ppm of chlorine.

If you want to shock the pool to try and make sure the filter is clear of any goo, your shock level would be 20ppm. So, use the reference I gave you above to figure out how much bleach to add when you test to take it up to 20. If you can go from sundown one evening to within two hours of sunrise the next morning without losing more than 1ppm of chlorine, have a CC reading no higher than 0.5ppm and have clear water, then you are good to go and can let the cl drift back down to 5-10.

Hope this information helps.