ater benches, though.

Dual Filter Cartridges
Gone are the days of those annoying filter bags. When you flip the DX4 S over, you can unlatch the bottom to release the dual filter cartridges. These snap apart easily for straightforward cleaning.

Filter Fullness Indicator
The little yellow light on the DX4 S flashes to let you know once the filter is full and needs emptying. Otherwise, you can let the machine run to its heart’s content.

Filters 4,233 Gallons per Hour
Talk about purifying. The DX4 S is a tank when it comes to tackling dirty water, and it can filter at a larger capacity than you’d expect from a robotic pool cleaner under a thousand dollars.

DX4 S Design
Compared to many of Dolphin’s other robotic pool cleaners, the DX4 S isn’t exactly a looker. It is colored in hues of gray, and the top-heavy handle makes you wonder how it can climb walls without creating resistance in the water.

The DX4 S weighs 22 pounds. It is remarkably nimble underwater considering how much it weighs, but it’s not a breeze to carry around or flip over to access the filter system. It doesn’t come with a caddy, but it’s certainly worth considering if carrying around the DX4 S will be an issue for you.

Despite its old-school shape and dreary color scheme, the DX4 S is an undoubtedly solid machine. The plastic exterior is durable and won’t scratch easily, and the plastic grips on the tracks won’t wear down with regular use. Plus, the scrubbing brushes are fitted with pliable-yet-tough bristles that’ll scrub grime from the surface without weathering or scratching your pool.

DX4 S Cleaning Power
In classic Dolphin fashion, the DX4 S arrives virtually ready to get into the pool. There is no assembly required, and you can likely have it in the water within 10 minutes of unboxing it.

Climbing Ability
Once the DX4 S started its initial cleaning job, it seemed to traverse the pool surface in a grid-like pattern. This is the smart technology at work, keeping tabs on where the DX4 S has and hasn’t cleaned.

Despite the tall handle that we thought might create underwater resistance, the DX4 S climbed the walls remarkably well. We didn’t notice it fall from a straight climb once. It reached the waterline on virtually every cleaning pass-through, doing a little shimmy at the top to cover more surface area and move over for the next strip of pool surface.

The DX4 S climbed up and over the curved coves on the bottom of the pool with ease, too. The only areas it struggled were the underwater steps and bench. It climbed the two bottom steps before falling backward, and it lingered on the underwater bench in the shallow end for a few minutes before giving up and moving on.

Scrubbing and Suction
The pool we used to test the DX4 S had plenty of visible debris littering the bottom. Several windy days had blown in leaves from nearby oak trees, as well as silty top soil that clouded the clarity of the water.

While the DX4 S worked, it was obvious it could pick up the larger debris with ease. It left behind a clean strip of pool flooring with each pass-through. We saw its scrubbing power at work in a particularly troublesome area of the shallow end where a patch of black algae was growing. The DX4 S climbed up and over the algae while the scrubbing brushes spun rapidly. When it descended back down into the water, it had all but cleared the algae from that patch of wall.

The Filters
The DX4 S uses dual filter cartridges. These are far, far easier to clean than traditional filter bags that can be messy and flimsy to work with. However, you access the robot’s filtration system from the bottom. This means you have to flip it upside down before you can unlatch the bottom panel and remove the cartridges for regular cleaning. Because the DX4 S weighs 22 pounds (not counting whatever residual water is in there after a cleaning), that can be a big ask of some pool owners. So, be advised, it’s a bit of a chore to flip this robotic pool cleaner upside down to access the filters.

But once you have accessed the filtration system, you’ll be amazed at just how much it captured. When we opened the dual filter cartridge after the initial run of the DX4 S, they were jam-packed with large debris like leaves, twigs, and flower buds. Best of all, they were also lined with a muddy sand mixture. This means the DX4 S actually scrubbed and filtered out smaller particles that were invisible to the naked eye.

This filtration system might be a chore to get to, but that’s where its shortcomings end. It’ll clean and capture debris with the best robotic pool cleaners on the market today.

Maintenance and Ease of Use
The multi-function power supply isn’t a one-button operation, but it’s still very straightforward. You can start and stop a cleaning job easily, and you can schedule the DX4 S to run once a week, twice a week, or three times a week.

We mentioned it before, but we’ll say it again: get the caddy. Yes, it costs more money. However, it’ll make your life a lot easier, especially if you’re concerned about lugging the DX4 S to and from the pool shed. Plus, it has a hook around which you can wrap the power cord.

What You’ll Love About the DX4 S
Under $1K
If you do your research, you can find the DX4 S for a very reasonable price, ranging from $700 to $900. Dependent on where you buy it from, it may come with a warranty to cover any mishaps in the first year or two.

Cleans Like a Champ
The DX4 S really does the heavy lifting for you underwater. It’s intelligent enough to choose an efficient cleaning route, and it delivers full cleaning coverage (minus underwater trouble spots like steps and benches). Just look in the filter after a cleaning job and we promise you’ll be impressed.

No More Tangles
The anti-tangle swivel is a game-changer. The DX4 S never got tangled up during its cleaning job – not even a few kinks. With constant use, you may need to stretch the cord out to relax any tension. But for the most part, it’s tangle-free.

Weekly Timer
The customizations of the timer are a nice perk, especially in the summertime when you’re running your robotic pool cleaner more frequently.

What You Should Know
It’s Heavy
The caddy is a great reliever for the heft of the DX4 S. But just be aware that it can be a chore to flip the machine over to access the filtration system. It’s easier to do so when it’s on the ground and you can tip it backwards.

The Remote is Finnicky
The DX4 S comes standard with a remote control. It’s a nice addition, but there’s a learning curve that comes with it. Unfortunately, the cleaner doesn’t come with an in-depth user guide on how to operate the remote control, so you’ll have to use a lot of trial and error to figure it out. If all else fails, simply use the power supply to command the DX4 S

Our Final Thoughts
Truth be told, it’s hard to find a robotic pool cleaner with this many working features for this low of a price. It delivers a deep clean and moves powerfully underwater, and its filtration system is on par with some premium-class models.

We wish it came with a caddy so its weight wouldn’t be such a burden, and it certainly won’t win any beauty contests with its drab color scheme and antler-like handles. However, it will save you hours of manual labor, and it’s a smart upgrade from traditional, power-hungry suction cleaners. So, if you value a lot of cleaning with minimal effort, you want the DX4 S in your pool