When buying a swim spa one of the most important things to consider is the swim current. Exploring the difference between a good swim current and a poor swim current will give you a few helpful tips for how to choose the right unit for you, and where the PDC Spas® swim spa products fall into place.

The 2 Types of Swim Current Systems

There are two main swim spa current systems in the marketplace.

Propulsion Systems. These swim spas use one or more propellers to power their swim current.

PDC: The patent pending TruSwim® propulsion swim spa series offers the market leading design with a hydraulic dual propeller, side-by-side design for a very wide, smooth and balanced swim lane.


Jetted Systems. By far the most common swim spa resistance system. These swim spas create their current using powerful jet pumps to force water through 2 or more swim jets.

PDC: The Synergy™ Series and the newly released Summit™ Series feature 2 or 3 powerful Elite Pro™ jets offering up to 690 GPM of resistance. MAKE NOTE—Many models in the market are not intended for swimming, but only for aquatic fitness. PDC Spas’ Vitality™ Series is a fitness spa and is marketed as such. Do not be fooled by other brands that feature a low powered, small vessel with jets not intended for swimming. You will be disappointed. Models of this type are for the cost conscious and although they serve a purpose for fitness, they do not provide a swimming experience.


At the end of the day, the type of resistance system the swim spa uses to create the current does matter, but what is more important is that the swim spa has the 4 elements that make for a good swimming experience.

Swim Spa Features to Consider

Regardless of how the current is generated, there are 4 features that make up a good swim spa current. Water current technology varies in price and performance. These are:

A Strong Current

If you’re able to easily out swim the current, you won’t get the full fitness benefits that swim spas offer. The current should be strong enough to challenge you. When making this significant purchase, realize your strength and stamina will increase and you may desire a stronger current in the days ahead to further your fitness goals. To get a powerful swim, you need a powerful resistance, which is better measured in GPM, gallons per minute, than HP for swim spas. Horsepower simply measures how much power the pump uses, not how much water it moves. Since water movement is the true measure of a swim current’s power, gallons per minute is a much better measurement.

PDC: The industry leading TruSwim® units offer up to 5000GPM of water flow, while the jetted Summit™ Series features 690GPM of resistance.

Variable Resistance Current

A current that can’t be properly controlled isn’t much good, no matter how powerful it may be. If you aren’t able to vary the speed of the water enough, the current may be too strong for some to enjoy the swim spa or too weak to be effective.

PDC: The industry leading TruSwim® models feature advanced digital control centers with programming of speeds from 1-20 , custom or standard workout sessions for multiple users with varying time lengths, varying speeds. The Summit™ Series, the more advanced jetted units, offer touchscreen control centers with a range in pump power from 1-6, also with customized workout sessions.

Smooth, Balanced Resistance Current

Along with being powerful and controllable, the swim current should also be relatively smooth and balanced. A jetted swim spa pool creates the water current with one, two, or multiple nozzles situated at the front of the pool. These nozzles or jets drive air into the pool and move the water from the front to the back of the pool. A single jet pushes between 250-500 gallons of water per minute in a focused stream. Depending on where the jets are placed, the water current depth is shallow and the width depends on the number of jets.

You will save money on a jetted swim spa, although aren’t true swim spas. When jets push air into the water, the current looks powerful but it’s mostly air and turbulence that you see. In actuality, the current isn’t strong enough for swimming. In order to swim, you will most likely have to use a tethering system. You must also make sure to swim in the center of the pool.

Additionally, the air and turbulence make it difficult to breathe while you are swimming. Choose a jet system if you have a limited budget and are seeking relaxation and less challenging aquatic fitness. Indeed, a jetted swim spa may the correct choice for you. A propulsion system delivers a more balanced, smooth swim lane for the best the industry has to offer in swim spas for the

serious fitness enthusiast and competitor. There is less air entering the water with this type of resistance providing true water only resistance. In addition, the propulsion system has a quieter operation than the jet pumps on the jetted version.

PDC: Both jetted swim spa series offer Elite Pro™ jets featuring a wide, narrow jet nozzle for the optimum in water movement. To make a wider swim lane, you need a wider jet. The Summit™ Series, has 3 of these jets, positioned side-by-side for a wide lane, and a third jet centered below the pair offering lift and balance to the experience. Elite Pro™ jets are also equipped with industry exclusive “swim fins”. These fins are mounted inside the mouth of the jet and are designed to greatly reduce the turbulence created by the jet pumps.

This design assures the ultimate in a jetted swim spa option. The TruSwim® propulsion series at PDC, is the widest, smoothest most balanced swim lane available. This is due to the dual prop, hydraulic design positioned horizontally for a full 29” width of swim lane. Unique to PDC TruSwim® Series, honeycomb grates covering the propulsion system “wash” turbulence from the water as the swim current enters the unit assuring a smooth resistance current.

A Wide, Turbulent Free Swim Lane

The “swim lane” of the swim spa is the area where you can actually feel the water pushing on you. The wider the swim lane is, the easier it is to stay in the current and the more enjoyable the swim experience is. Turbulent water is difficult to swim in as it pushes you around in unpredictable ways. Poorly designed shells cause this. Most people looking to buy a swim spa don’t realize that the interior design of the swim spa actually has a big part in effecting how well the swim current performs.

Straight, unobstructed interior sidewalls allow the water to flow directly from the resistance to the return for a turbulent free experience. While this is a manufacturing challenge, many brands mold curves and shapes into the walls for easier manufacturing and a visual appeal in the showroom, discounting the actual swim experience. A shell design with curves and obstructions narrows the swim lane as the later bounces off these “curves” creating a turbulent water body with no real path of resistance. Swimming in a narrow swim lane is very difficult. If your body moves to the left or right you can be pushed out of the swim lane and have to fight to get back in. Add the turbulence element, and the swim experience may be disappointing.

PDC: With decades of experience in the industry, PDC has the expertise to build straight sidewalls in their TruSwim® shell design. The straight sidewalls greatly reduce the amount of turbulence in the swim lane., allowing the strong current from the wide propulsion outlets to flow smoothly in the center of the shell, straight to the therapy end where a “bullnose” forces the current to split, forcing it to return to the suction grates tightly along the sidewalls, not interfering with the swim lane current. By forcing the water up the sides – instead of back into the swim lane – the TruSwim® shell design eliminates the turbulence caused by the current “bouncing” off of the walls of swim spa with curves.