Here is a very good reason to wet test a spa you are thinking about purchasing. Unless it is an inexpensive spa with few jets you will likely discover that all the jets cannot be used all of the time! With many brands, in fact most all, the spa you were just told can seat 6, can only provide massage to 2 - 4 of them at one time. Virtually all spa manufacturers use Diverter Valves so that they can claim high jet counts. They can provide good pressure to some of the jets with this Diverter Valve but, as the name suggests, they are diverting water pressure from one set of jets to another! Bullfrog Spas is THE MAJOR EXCEPTION! Their unique plumbing is far more efficient than that in any other hot tub, hence they use NO DIVERTER VALVES! (Click to see)
So what is a Therapy Zone? Well, some of the more creative marketing people realized that "Diverter Valve" sounded too much like what it actually does and that doesn't sell well. These folks came up with the new name, "Therapy Zone". Sounds so much better, doesn't it? It's a sophisticated Diverter Valve - and you still cannot use all of the jets all of the time, hence not everyone in your hot tub gets a massage!