“99% trichlor” sounds like a mic-drop statistic, but it’s also one of the most persistent sources of confusion in pool care. We sit down with Bob Lowry to untangle what that number actually means, why “purity” is not the same thing as “chlorine strength,” and how the industry’s use of available chlorine (based on a chlorine gas reference) warps the way products get talked about on the truck and at the counter. We walk through the real chemistry behind the label: what free chlorine is doing i...