A childhood belief about swimming pools

When I was 8, I would go to my elementary school's after-school program and every Friday we would all walk down to the pool at another school. The teacher that was with us made everyone sit down (every week) so he could explain the rules. The most important rule was to not pee in the pool because it had special chemicals in it that would make a purple ring would appear around you and everyone would know you did it and make fun of you. He even told us this whole elaborate story about how when he was little his brother told him the same story and he didn't believe it and when he peed in the pool the purple ring appeared and everyone made fun of him for the longest. Then, at my summer camp, one of the counselors told a similar story, except at that pool, apparently, the chemicals made the water turn red instead of purple. Needless to say I always made sure I got out to go to the bathroom after that (but only at those 2 pools!) Long story short, the tales were so convincing that I believed them all the way up until yesterday when I first heard about this site. I was reading the list of the most common beliefs and saw it listed, so I asked my mom if it was all a lie and she just laughed at me! I was so stunned! I couldn't believe it! I felt so ashamed that I was 15 years old and just finding this out!