Algae every week even though the test kit shows plenty of chlorine? That headache usually isn’t bad luck, it’s bad math. We dig into the most common rookie mistakes new pool service pros make and show the chemistry behind why a pool can read “sanitized” while algae still wins. The big unlock is understanding cyanuric acid (CYA) and how it binds most of the chlorine in the water, leaving only a small active portion available to kill algae. From there, we make the fix practical: stop gue...