Yes, there are retractable fountain heads which install in the floor of an in-ground tub. You simply move a diverter valve on the filter/heating pump and the water pressure brings it up to do it's thing.
When you want to use the spa, you return the diverter valve to the circulate position, and you are ready to heat and soak.
Alternately, you can simply plumb in laminar-flow fittings around a spa, again with a seperate pump or a diverter valve from the cirulation system, and shoot them into the spa from the deck around the perimiter.
Lots of ways to do it.
However, an open in-ground tub must be heated every time you wish to soak, and this takes time. This tends to make it much less likely to see long-term use. Also, most in -ground shells are very plain and frankly, uncomfortable when compared to the high-tech designs of most self-contained spas.
