The second piece of kit is effectively a huge battery with a few simple controls on board. There are three different battery sizes available, each offering more power and power than the last. I received the top-tier battery, called the X Pro 10, which weighs 26 pounds on its own and is rated at 60 amp-hours (Ah). This provides a maximum run time of 10 hours, albeit on the device’s slowest setting. (There are two lower capacity models available with 30 Ah and 15 Ah capacity, respectively; note that these also have lower GPM output power in addition to shorter maximum run times.)

Photography: Chris Null

Photography: Chris Null

The two components are connected by a thick cable; When not in use, it wraps around the jet unit handle for storage. The only other element of note is the inclusion of a metal tether cable on the jet unit, designed to wrap around a pool ladder or other anchor fixed to the top to prevent the jet from falling into the water (and taking the battery into your drink). In practical terms, I doubt many pools have a proper anchor point. I was never able to use the guy wire and, for what it’s worth, I never felt any concern about the plane slipping and falling.

Aside from charging the device (which can take up to seven hours), the only real setup required is adjusting the height of the jet in the water. iGarden suggests one of two settings: If the top of the jet is 2 to 4 inches below the water surface, the current is gentler and more stable, best for swimming. Alternatively, you can place the top edge of the jet at or slightly above the water line, creating a much bolder but less drafty surface spray, ideal for water-filled playtime. Height is adjusted via a somewhat crude system of knobs and brackets attached to a movable frame on the back of the device; The design is awkward but in the end it works quite well.

Mark a bathroom

Operationally, the Swim Jet is simple: your main decision is what power level you want to run the device at. There are four standard power levels available via a button on the top of the power pack, plus a turbo mode that runs the plane at its maximum speed, but only for five minutes. A final mode, coded “PF” on the battery pack display, is designed to mimic open water, cycling through various speeds to evoke the ebb and flow of the ocean. The only other real option is a timer that turns off the jets after between 15 and 90 minutes. (In the iGarden app, which pairs over a 2.4GHz Wi-Fi connection, the same options are available but it’s considerably more intuitive to choose.)

I did most of my testing with the Swim Jet in underwater swim mode rather than overwater play mode, largely because it’s easier to quantify its performance this way. Plus, my wife is an experienced swimmer, which gave me the perfect guinea pig to determine how effective the Swim Jet was for an in-water workout.

I quickly found that power level 3 was the sweet spot for creating the perfect amount of resistance for vigorous swimming, although slower swimmers could get away with level 2. In the water, you quickly discover how the current level decreases as you move away from the jet. At point-blank range, along the wall, the current is too strong to swim in, but at the other end of the pool, more than 30 feet away, the flow is not even noticeable. At a distance of 5 to 10 feet, you’re in the sweet spot, being able to swim in the current while staying almost exactly in the same spot. This can get a little boring over time, so eventually my wife decided to swim back and forth, letting the current push her toward the far wall, and then swim back against the current until she reached stasis position.

While the unit can theoretically last 10 hours on its slowest mode, it soon becomes apparent that the more powerful (and worthwhile) modes eat up much more battery life. At level 3, the system ran for only two hours in my testing, and higher power levels have an even shorter lifespan.

As far as training goes, it’s legit. Swimming against the current is hard work and you can quickly see if you are keeping pace based on your body position in the pool. I deferred to my wife about how this compared to real swimming, and in her opinion, a full workout with the Swim Jet was about 80 percent of a lap lane workout: solid but not perfect, even though she said she felt like she was swimming at the same relative speed. Still, the Swim Jet training was a little easier. The difference, he theorized, was that in the pool you not only swim at a pace, but you move your body through space, pulling it through the water. With Swim Jet, you don’t have to cover any distance, which makes things a little easier. Of course, you can always swim longer, at a higher power level, or closer to the jet if you want to close some of that gap.