So I'm having a Halloween party in a few days and am planning on having guests bob for apples out of a tub. The tap water here has 1.5ppm FC. This doesn't seem like enough to kill germs fast enough to prevent them from spreading from guest to guest. What would be a safe FC that would kill germs within a reasonable amount of time and not give the guests a free facial chemical dermabrasion.
I realize this is a little out of the realm of the typical sized body of water discussed here. I'm hoping someone might have an idea.