Hi Vivian,

Good idea to change off the pucks - your CYA is high enough already. With that high CYA, you need to keep 8-15 FC. Less than 8 and your algae is very happy!

If I understand your testing method correctly, you're probably overestimating your FC, meaning you're probably not at 8 after all. When you say "regular" water, I'm a s suming you mean tap water. If your tap water has any chlorine in it, then you're testing the chlorine from your pool -plus- the chlorine in the tap water which will lead you to overestimate the chlorine in your pool. Use distilled water instead.

With algae an issue and needing to consistently test for higher levels of chlorine, you really do need a better testing kit that can handle higher FC levels. Of course, the PoolSolutions kit will do that but I'm unsure if you can get one in a timely manner, if at all anymore this year. I've heard that there's a Taylor kit that's good but I've not had experience with it. While the Wal-Mart 6-way test kit tests almost everything you need, it only tests chlorine to 5 without dilution, and it's total chlorine, not free chlorine.

Also, because you have a concrete pool, you should run a calcium test.