A hot tub, despite the fact that water temperatures are higher than swimming pools, still may be a better place to hang out than the public water park. At least you know who is going into the water (and who is not going in the water!).
A recent article on Yahoo explains that water parks and public swimming situations may have more undesireable accessories in the water than one would care to imaging. Water Park Article on Water Quality
If anything, having your own above ground pool or hot tub may be more sanitary than getting an accidental gulp of the public water park stuff. Water parks do pour on the chemicals and try their best to maintain safe bacteria levels, but in this article it is pointed out that for some reason, even adults may squint their eyes and let ‘er rip in the pool, first because they are anonymous and second because it may seem convenient at the time.
Sure, fish go to the bathroom in the water, but the ocean has a large amount of water and natural ability to avoid concentrated contamination (although I would not necessarily advocate drinking ocean water either). Owning your own pool or hot tub means being responsible for your own water quality, and if you desire, you can have cleaner water than the water park.
There are also enzyme treaments for hot tubs (and pools) that reduces the need for chlorine or bromine. However your spa will still need some of the chlorine or bromine sanitizer. Mineral sticks can also help reduce sanitizer needs.
It has yet to be officially approved as a replacement for chlorine or bromine, but is already successfully being used as such by several hot tub owners.