LOL, it helps

Just to clarify my post above, I have had the chlorine levels in my pool up into the 30-40 ppm range for extended periods of time (don't ask!) and it only took one scoop of powder to produce pink. It is possible, and I think one of my fellow mods is actually trying this out for clarification, that extremely high chlorine levels may bleach out one scoop of powder. However, even if that's so, you shouldn't find that level of chlorine in any source of drinking water.

Janet