Pregnancy is a relative contra indication to using the pool. Case control studies have found that an increase in body temperature is associated with an increase in fetal malformations. To minimise this risk, core temp should not exceed 38 degrees C during pregnancy.

So don't go into really hot hydrotherapy pools. 28 - 30 degrees is ok. Having said this, I know of other physio's that specialise in hydrotherapy who have continued to work in hydrotherapy pools (about 34 degrees) well into there pregnancy without ill effects.

As for pool chemistry, it is a good idea to learn a little about pool chemistry, so you can sus out how safe a pool is before getting in. This is especially important if staff have sensitive skin. Bromine seems to flare up the skin more. there are some good courses around which can teach you about this sort of stuff.