Think of all the disgusting things that are left in public pools (especially water parks).

1. Fecal matter
2. Cum
3. Boogers
4. Blood
5. Puss
6. Bandaids
7. Dandruff
8. Fold cheese from fatties
9. Pubic hairs
10. Spit / loogies from coughing while sick
11. Toe jam
12. Urine
13. Ear wax

Sure, they add tons of chemicals to kill all that stuff, but now you are soaking yourself in heavy chlorines and other acids, on top of the now dead, but still present items listed above.

Just the thought of it makes me gag.