While this is a question that only you can answer, we do have a few tips to make it easier for you.

Length

This may or may not seem obvious to you, but it comes up often enough that it bears repeating; you should make sure that whatever model you buy will actually fit in your yard.

Thankfully, swim spas are fairly compact. You don’t need to have a huge body of water in order to get a good workout. Keep in mind that the smaller ones tend to be about 12 feet long, and that’s about twice as high as the average person. With powerful swim jets, you won’t be able to swim all the way up front in any case.

Swimming System

Not every swimming system is built the same; there are at least three major types of swimming systems on the market today. The most common system involves using water pumps (the same kind used for jets in hydrotherapy spas) to move the water so you can swim at your own pace. When evaluating these, it’s important to make sure that it will be strong enough to give you a good workout. You’ll want to look out for a swim system that pushes out the highest volume of water rather than simply having super-strong jets. The best of these systems have an entire jet pump tied to one or two jets at maximum, and the best ones use 2-3 pumps in tandem. Keep in mind that if you don’t already swim regularly, you may end up getting better at it as you have more practice.

There is also a very inexpensive and simple swimming system that is very commonly offered (sometimes as an addition to other swimming systems); it’s called a swim tether. Basically, you put on a padded belt and tether it to an anchoring point on the swim spa, generally put on a raised bar so you don’t tangle up on the tether. It’s easily the least costly option, but it comes with the disadvantage of needing setup when you want to use it, and it’s not going to give you as good training for real swimming since it’s the tether holding you back instead of water flow. There are some swim spas that only use this system, but generally it’s thrown in an exercise package alongside another type of system.

Longevity

Buying a swim spa is an investment, so you should make sure that it’s built to last. The water you fill it with is not only extremely heavy, it applies force horizontally across all parts of the shell. That’s why it’s important to make sure that your swim spa has a very strong construction.

To put things quite simply, Marquis’ ATV swim spas are the absolute best in this respect. Their shells are a made out of a thick layer of custom-made resin, and they are supported by a unibody fiberglass support structure. It’s built so strong you can likely expect your next of kin to inherit it.

For all other brands, there are two things you should check; the shell and the structure. Shells are most commonly made out of a thin layer of formed acrylic that is bonded together with multiple layers of fiberglass. The thing you want to check for is the thickness; generally speaking, the thicker it is the better it is. You can usually tell by looking at the very edge of the shell where it meets the cabinet, but you might want to ask the salesperson if they have a sample or if they can open the cabinet to get a better look. That being said, the strength is also determined by how the fiberglass is applied; a shell can be just as strong while being thinner if it is made with woven fiberglass sheets instead of using blown fibers that are randomly laid across. That being said, that form of fiberglass is more expensive so it’s fairly uncommon.

As for the structure, you’ll want to find one that is made of pressure-treated wood. The treatment is vital; pressure-treated wood has resins forced into it’s pores which makes it impervious to rot and water damage. You can probably imagine what happens when they use untreated wood for the frame. You might also come across metal frames; we have had experience with them in the past and we strongly recommend against them; they tend to be made with low-grade steel that is subject to rusting, and our experience with them left us with spas that buckled and bent under the weight. They typically aren’t made with the kind of metal that will spring back.

Hydrotherapy

The entire reason why we call it a swim spa is because they are designed to relax in. Most manufacturers will include a heater for year-round use, so why not set it up higher for a more soothing experience? Most also include the option to install hydrotherapy jets so that you can also get the traditional hot tub experience. In fact, some manufacturers have better hydrotherapy in their swim spas than they do in their hot tubs!

Depending on how much you value having the hydrotherapy, you may consider a ‘dual temp’ model swim spa. As most people prefer to swim in cool water and relax in hot water, dual temp models were invented so that you can have it all. These models come with two separate bodies of water; one for swimming, the other for relaxing.

The downside to having this luxury is that dual-temp models tend to be more expensive than traditional models. In fact, they are almost as expensive as buying a swim spa and a hot tub separately. One manufacturer, in response to this expense, decided to not make dual-temp swim spas at all, opting instead to make a companion spa that attaches to the corners of their full-featured swim spas.