[Greysard]

that's assuming that they used chlorine

Without chlorine the pool becomes an algae swamp in just a couple of days. Algae will stain the walls of the pool, and the water will smell bad. It's much cheaper to add chlorine, especially when one pool services hundreds of guests.

[CharlesWayneCT]

There are other treatments for pools, although I don’t know if any of them are sperm-friendly.