We just bought a home with an older pool and want to care for it ourselves but the first month has been full of frustrations. Thought we finally had it figured out and then came home after the weekend to a green pool. Ran a test and no chlorine even though we had floaters in. Pool place sells me 5 bags of shock and nothing happens. We have been going back and forth to pool co since we purchased our home and I feel we're not getting anywhere so I started doing some research and found this site. Our CYA has always read 100 on the pool store printout but they have never told us to do anything about. Guessing this is why our chlorine was not doing its job. Yesterday we emptied 30-45% and refilled. I went and bought the cheaper Walmart test with cya until I get other one ordered. Now it shows our CYA at 60. Based on chlorine/cya chart I want to raise to 24FC to shock so I emptied 7 bottles of bleach into the pool 3 hrs ago. I don't have a test to measure what my FC is now. What is suggested I do next? And is 24FC high enough for the algae? I saw another chart that said 34FC. I really prefer not going back to the pool store for another reading but that may be my only option.