Our CF doctor told us that all hot tubs/jacuzzis/etc were not the best idea. His explanation was that the germs breed in them and then when you turn on the bubbles/jets that the aeration of the water means that you are breathing in whatever is in the water. It is similar to when you nebulize, except that the particle size is different, of course. He said that the water with chlorine in it (like outdoor tubs) are usually safer than the home tubs because of all the bleach, but that one of the MOST dangerous places to go if you have CF is a hot spring (like at Yellowstone, etc) which I had no idea about! That said, we have to let the kids be kids and not worry about every little thing or we will never let them enjoy living. I just wanted to let you know what we were advised against for your own information.
All the best to you!