I think it's "No Speedo's Based on the Repulsive Factor" and "No Eating Ice Cream Cones Based on the Crumb-in-the-Filter Factor" (They don't seem to mind if anyone eats ice cream in a dish. Maybe I'm wrong.)
Oops - now I see that it's no balloons - not no ice creams cones. Hmm... "No balloons based on the fact that they may pop, scare someone, cause any number of heart attacks in any number of swimmers, and result in a massive multitude of lawsuits against the owners of the pool - not to mention the lifeguard on duty (if, in fact, there is a qualified lifeguard on duty at all).... Yes. That's what I think the sign means.