I've had my pool for 1 year and just discovered this group. My water is clear and I've had very few problems. I have a 30,000 gallon gunite pool with pebble finish and ozone/uv system. I'm trying to wrap my head around the chlorine calculations I'm seeing. I usually run on the very low end (between 1 & 3). But, just playing with the calculator, it says because my CYA is 70 my target FC should be 6 - 10. Is that true? I've never had chlorine that high and always had clear water. Is it even safe to swim with FC that high?