What is the function of a circulation pump in a hot tub?

Circulation Pump: This pump pulls water from the filter and pushes it through the heater returning it to the spa. The circulation pump also filters the water to keep it clean and clear.

It provides the necessary flow to allow the heater to constantly maintain your set water temperature. Spas without circulation pumps rely on low speed on larger horsepower pumps turning on periodically to provide filtration and the flow required for heating. The circulation pump is the most efficient method to provide flow for filtration and heating.

How many pumps should a hot tub have?

This depends on you and what you need the tub to do and set up of specific models of spas. Generally hot tubs have one main pump with booster pumps fitted for extra power. Air blowers can also help to boost performance of the jets, while circulation pumps have no effect on the performance of the spa or hot tub other than to maintain and filter the spa water.