Many people think the more jets you have, the better your massage. This is not necessarily true. We also have to look for a balanced relationship between the number of jets, jet size (nozzle diameter), and pump size.
When you're looking at the confusing panorama of jet offerings, it's hard to determine which of them is best. Keep this simple thought in mind: The only jet that does you any good is the one aimed at your back. The real questions are "How many people use the tub at the same time?" and "Do those people each need their own jet?". Any jet not on somebody's back is wasted. Don't buy more jets than you need for the number of people in your tub. Some manufacturers offer many jets instead of fewer high-quality ones. In most cases, you can't use all the jets at once because the pump isn't big enough to handle them. This type of hydrotherapy system includes a director valve that you use to select one group of jets at a time! They don't all operate at once.
Large-nozzle jets permit more water to flow than small jets. More water flow means a firmer massage. A spa with many small jets could have the same massage action as a spa with fewer large jets. You need to compare total diameters of all jets in relation to the pump size.
A large jet with 15-20 GPM (gallons per minute) needs 1/4 Hp to produce massage action. If you increase the number of jets, you must also increase pump size or decrease jet size to get proper massage action. Some manufacturers try to fool you into thinking their spa has increased hydrotherapy action because it has many jets. Their claim is true only if total nozzle diameter and pump size are larger than comparable models.
Our Advice: Buy a hot tub or spa with the correct number of jets for your needs. If you need or want very firm action, consider fewer large jets and a bigger pump. Watch out for salesmen that brag about the number of jets they have. Ask for a demonstration to see if all jets operate at once.