Hydrotherapy dates back to the Roman Empire. In the beginning, pools filled with warm water were crafted of stone.

It has been only about 40 years since hot tubs were nothing more than wooden barrels filled with hot water. Then they got bigger, and were equipped with water jets and air jets. Later they were made of molded plastic instead of wood. When that happened a new industry developed almost overnight.

As spa industry growth continues, the consumer is left with the "how-do-I-choose-the-right-one" question. We can help.

The spa experience is without a doubt enjoyable and therapeutic. According to Jeff Kurth, Chairman of the National Spa and Pool Institute (NSPI) and CEO of Marquis Spas, "A spa provides buoyancy that eliminates 90 percent of the force of gravity on the human body. Heat dilates blood vessels and increases the flow of nutrients to damaged muscle tissue while flushing out toxins that make you feel sore. The hydrotherapy part also helps to massage the toxins out of the muscles."

Kurth further commented: "Depending on the size, number, type and location of the jets, various types of massage can be achieved."

We agree that you really can feel the results. And the stress relief is pronounced.

Why get a fancy spa as opposed to one with fewer or smaller pumps and fewer jets? The more options, the better your chance of finding comfort and satisfaction for the whole family. Not every jet pattern in every location of a given spa will please everyone. Some will feel only OK; others will work wonders. Someone else in your family might find the greatest comfort in the position you like the least. The more options you have, the better served you and your family will be.

Today spas are available with up to three motors - just to pump water through the jets. Multiple controls and multiple compartments make it possible for one person in the family to have a vigorous massage while others can enjoy other options.

* Possible features:

-An airtight spa cover. A good one reduces energy loss when the spa isn't in use. Our favorite is vinyl-encased foam with a tapered top. Make sure it is an ASTM listed locking safety cover. A locking top will keep energy in and toddlers out.

-Solid insulation between the spa and the skirt. Fully insulated units are more energy-efficient.

-A built-in ozonator can reduce the amount of chemicals needed to kill bacteria in the water. If you are allergic to chlorine or bromine, an ozonator can be used in conjunction with silver, which is a natural bactericide.

-Two filters are better than one. Units with multiple filters clean faster and better.

-Measure the horsepower of the pumps, the number of jets, the number of controls and the number of stations. These are key elements to comfort in a spa.

-Check with your doctor and your insurance carrier. Some insurance companies will cover the cost of a home spa. If you have no insurance coverage, check with your accountant to see if you can deduct all or part of the cost of your spa from your income taxes.

-Spas, like swimming pools, can be used year-round. But as we know, swimming pools are best on hot days. This is not necessarily so with spas. We think spas are most fun when it's cold. There is nothing like sitting in a spa on a cool fall or winter early morning looking up at the stars.

The National Spa and Pool Institute helps set safety standards, and Underwriter's Laboratories (UL) tests spas for safety. Only those products approved by UL should be used. Folks with a heart condition or high blood pressure should check with their doctor before using a spa.