Kids dont have to pay, their parents pay for them. This place is not a free babysitting service. Not only does the parents need to pay, but the parents have to stay with their kids also.
It's a public pool with lifeguards who need to get paid, so charge everyone a small fee or charge the adults a large fee and let the kids in free either way they will get their money. At least this way it feels like a deal to me. And kids get paid for chores so you can teach them to save money for the pool.
Thanks! Your answer is awaiting moderation.