A: The importance of this question is often over-rated, and more often misunderstood. Horsepower does not necessarily equal spa power. For full explanation of spa pumps and how they work, visit the Hydrotherapy section of our web site, and read the information labeled "Power and Control."
In a nutshell, you want to review the overall ability of a spa to generate water volume. Water volume equals power. Pumps alone don't produce waterpower; a spa with a powerful pump and an inefficient plumbing system won't produce the volume you're looking for. Jet placement within the plumbing is also important. Spa plumbing that places jets in a straight row along a plumbing line may produce unequal power to each jet. Plumbing with proper jet clustering and an appropriate pump size will give you the most efficient type of water volume and flow.
If you really want to test water volume power, stick your hand inside the spa when it's filled with water. Look for air controls and massage selectors that add air bubbling to the mix, or move water volume from one seat to the next. These selectors should be simple to use, and at arm's length from each seat. The feel of the water flow and your ability to adjust it to your liking is much more important than the horsepower of the pump.