When I go to a water park I wear my compression vest shirt and 1 or 2 compression shirts folded up and a black t-shirt over it.
The chemicals in the water haven't ruined my compression shirts. I have a few small holes, but that I don't believe is due to the chemicals, just being worn a lot.
I've always worn my compression vest shirt and my compression shirts folder and they don't really bother me in the summer. I just got my binder vest like thing so I haven't worn it last summer. But I would think it wouldn't be too hot.