My cya level is currently 35, I'd like to get it up a little betwen 40-50. I don't normally visit the pool store for chemicals, but bought a couple of 3 inch trichlor pucks, and put one in the feeder to raise the level some. Plus, I'll be gone next week on vacation, and this will help keep the algae at bay. Does anybody know approximately how much 1 puck will raise the cya level on a 18'ft round pool, approx. 8600 gallons.