water aerobics perth northern suburbs

Hi all, want to do some light exercise during pregnancy (needs to be light due to a condition I have)... so thought water aerobics or walking in a pool would be ideal.
But, dont really want to be breathing in all that horrible chlorine..
Anyone know of any places that I can do classes or swimming in a pool that's maybe salt water or something, even with a private physio or trainer in a home heated pool?
I know of Freo acquatic centre which is salt water, and I think Bayswater is low chlorine, but both are too far from me. I am close to Warwick train station.
Also, whats the temp of water allowed to be when exercising in it? Or am I better to take a temperature thermometer of my body temp? and what is the limits for this?
Thanks,