Dolphin Sigma Review

This is the new king of pool robots.

Updated for 2026, the Sigma hosts a slew of new upgrades that make it even better. Part of the Dolphin ProLine, Maytronics' top Dolphin lineup, it has a gyroscope, triple motors, SmartNav 3.0, NanoFilters — and it now fixes one of the biggest weaknesses of every pool robot.

Every robotic pool cleaner I have ever tested shares the same embarrassing weakness. It powers across the floor, climbs the walls like a champ… and then it hits the main drain and parks there like it found front-row seats. The suction locks onto that raised drain cover, the tracks spin, and your thousand-dollar robot spends the next two hours polishing one square foot of your pool.

The new Dolphin Sigma just killed that problem.

Maytronics added a new center brush upgrade right in the middle of the robot, and in my testing, this thing has rolled over my main drain every single time. Weeks of daily runs. Zero hang-ups. Not one. It's a separate add-on, but it completely changes the game.

Hey guys, welcome back to the Pool Nerd. I'm Justin, your resident pool aficionado. Over the past five years I've tested more than 40 robotic pool cleaners in our test pool — everything from $100 budget bots to $4,000 flagships — and I've reviewed the Sigma before. It was already my pick for the most advanced robot on the market.

But with so many new upgrades, it was time to update this review. A new center brush add-on. A more refined myDolphin Plus experience. And the same three commercial-grade motors, gyroscope navigation, and NanoFilters that made it famous.

Below I'll walk you through the new upgrades, the tech that separates the Sigma from every other robot, how it stacks up against the Dolphin Premier, the Dolphin Quantum, and even other brands like the Clear UV — and where to grab the best deal. Let's get into it.

The Center Brush: The Main Drain Problem Is Finally Solved

Let's start with the headline feature, because it has earned that spot.

One important note before anything else: you do need to add this to your cart at checkout. It's usually right on the product page — just tick the box to add it. And know that you can always buy it later if your robot ends up getting stuck on the drain. On about 85% of pools, you won't even have the problem.

Why Pool Robots Get Stuck on Main Drains

Here's the thing about pool robots and main drains: those raised drain covers at the bottom of your pool are a robot trap. As a robot drives over one, the dome lifts the tracks off the floor while the suction port clamps down on the cover. The robot loses traction, the intake seals against the drain, and it just sits there.

If you've ever fished a robot off your main drain, you know the routine. It is the number one complaint I hear from pool robot owners — and until now, no manufacturer took it seriously.

What the Center Brush Actually Does

The Sigma's answer is the new center brush. It sits in the middle of the chassis, between the spinning scrub brushes, and it rapidly oscillates back and forth as the robot moves.

That does two things. First, it gives the Sigma a third point of scrubbing contact, agitating stubborn grime loose before the suction takes over. Second — and this is the part I care about — it keeps the robot moving across raised drain covers instead of letting the intake catch and hold.

Installing It Takes About Two Minutes

It's genuinely easy to install yourself. Everything you need comes in a small white accessory box, and all you need is a screwdriver.

Flip the Sigma over, back out the screws holding the center panel, and lift the panel off.

Drop the roller into the channel, line up the end caps, and press it into place.

Then screw the panel back down and you're done.

That's the whole job. One to two minutes, start to finish.

And the bonus? That oscillating brush is scrubbing the whole time. More brush contact means more algae and biofilm getting knocked off your floor on every pass. It is a cleaning upgrade and a reliability fix in one part — and it removes the last excuse anyone had for not calling the Sigma the complete package.

Three Commercial-Grade Motors

Now let's talk about what was already under the hood, because the Sigma does not disappoint — it was already the top of the ProLine.

The Sigma is the only ProLine residential robot I've tested with three commercial-grade motors. These come straight off the platform Maytronics uses for its Dolphin Wave commercial robots — machines that clean resorts, water parks, and public pools, and sell for $2,000 to $8,000-plus.

Three motors means suction that filters over 75 gallons of water per minute — north of 4,500 gallons per hour. In my testing, nothing else in the residential market comes close. Leaves, sand, fine silt — the Sigma inhales it all without slowing down.

Here's the kicker: the Sigma pairs that commercial muscle with features the Wave robots don't even have. NanoFilters. The myDolphin Plus app. A weekly smart timer. A 3-year warranty. You are getting commercial power with residential intelligence — at a fraction of commercial pricing.

Gyroscope Navigation and SmartNav 3.0

Power without a plan just makes a mess faster, and navigation is where the Sigma pulls ahead of everything else — including other Dolphins.

The Sigma carries an onboard gyroscope — the same category of motion-tracking tech used in aircraft — paired with SmartNav 3.0, the most advanced navigation software in any Dolphin. The Sigma tracks its position in real time. It knows where it is, where it has been, and what is left to clean.

No random wandering. No missed patches by the steps. In my testing, coverage was methodical: you can watch it work the pool in clean, deliberate passes and hit the spots lesser robots skip.

If you've owned a robot that leaves those maddening dirty patches behind, the difference is obvious the first time you watch the Sigma run. It's also why the Sigma is my top pick for large pools and awkward gunite shapes.

NanoFilters

A pool robot is only as good as its filter, and this is where most robots fall apart. Budget cleaners ship with loose plastic mesh — fine dirt, algae, and bacteria sail right through, and your water stays cloudy no matter how often the robot runs. And a lot of cordless cleaners don't have the power to use anything better.

The Sigma ships with dual top-loading filter cartridges and includes Gen-2 NanoFilters in the box. These are tightly pleated polyester filters that trap the microscopic stuff standard mesh can't touch — fine dust, silt, and algae.

In my side-by-side testing, the difference is night and day: the NanoFilters pulled out clouds of fine particles the standard mesh never even saw.

And because everything loads from the top, cleanup is painless. Pop the cartridges out, rinse them, drop them back in. No flipping the robot, no wrestling with latches, no disassembly.

The myDolphin Plus App: More Features, Easier to Use

Now the app — because this is where the Sigma widens the gap between it and the competition.

I've tested the companion apps for every major robot brand, and most of them are an afterthought. Cordless robots are the worst offenders: their apps connect over Bluetooth, which means the moment the robot goes underwater, the connection dies and the app turns into a paperweight.

The myDolphin Plus app is a different animal. In my experience it is the most feature-complete robot app on the market — and at the same time, the easiest one to use. The Sigma's Connect Anywhere power supply links to your home Wi-Fi, so the app works whether the robot is underwater, across the yard, or you are across the country. Forgot to run a cycle before guests arrive? Open the app from the airport and hit start.

Inside the app you get:

• Real scheduling — exact days and exact times, like Fridays at 4 p.m. and Sundays at 10 a.m., not vague intervals
• Remote drive — steer the Sigma straight to a dirty spot from your phone
• Live stats — gallons filtered and distance traveled
• Siri voice control — say "Hey Siri, clean my pool," and the Sigma goes to work

Setup took me under two minutes: plug in the power supply, link your Wi-Fi, done. Plenty of robots claim app control. In my experience, the Sigma is the one that delivers it without the headaches.

The Weekly Smart Timer: True Automation

The feature I would never give up, though, is the weekly smart timer.

Set your schedule once, and the Sigma runs itself — every day, on time, without you touching it. My routine is one touch a week: empty the filters, rinse, done.

Compare that to robots without a timer, like the Dolphin Nautilus CC, where you are walking out to the pool every single day to press a button. Or cordless robots, where you are going outside twice a day — once to fish it out and charge it, once to throw it back in. That is not automation; that is babysitting.

The Sigma's timer is set-and-forget in the truest sense, and once you live with it, there is no going back.

Waterline Cleaning and the Dual Stabilizer

The waterline is the dirtiest part of any pool — it is where body oils, sunscreen, and scum collect — and most robots ignore it. The Sigma attacks it.

With three motors driving it, the Sigma climbs walls like a gecko and scrubs all the way up to the tile line. The secret is the Dual Stabilizer: the handle on top doubles as a float that drifts toward the surface as the robot approaches a wall, helping it grip and hold position right at the waterline.

Of every Dolphin I've tested, the Sigma is the strongest waterline cleaner — and if you have ever scrubbed that scum ring by hand, you know exactly what that is worth.

Sigma vs. Premier vs. Quantum Pro

So where does the Sigma leave the rest of the Dolphin lineup?

For years, the Dolphin Premier held my number one spot. It is still a monster — dual commercial motors, Multi-Media filtration with an oversized leaf bag, and the Media-Alert light that tells you when the filter is full. If your pool drowns in leaves every fall, the Premier is still the leaf-eating king, and I still recommend it. If you don't care about the app, I'd still point you to the Premier.

But the Sigma changes the math at the top. Three commercial motors instead of two. A gyroscope with SmartNav 3.0 instead of standard navigation. The full myDolphin Plus experience with remote drive, exact-time scheduling, live stats, and Siri. And now the center brush, which erases the one reliability gripe that applied to nearly every robot on the market — the Premier included.

Feature for feature, the 2026 Sigma is the most complete pool robot ever made, and it takes my crown this year.

The redesigned Dolphin Quantum Pro still deserves a mention as the value play — ProLine features, app control, the massive XXL MaxBin, and full floor, wall, and waterline coverage at a lower price. If your budget stops there, you won't regret it.

But if you want the best? For 2026, the answer is the Sigma, and it is not close. If you want the full lineup side by side, I break every model down on the compare Dolphin pool cleaners page.

Clear UV and Clear S

Outside the Dolphin family, only two robots I've tested belong in the same conversation as the Sigma: the Clear UV and the Clear S.

The Clear UV is a commercial-grade corded robot with four motors, quad scrubbing brushes, proprietary UltraFilters in a top-loading UltraBasket, and a polished app with a weekly timer, manual control, and a pickup mode that drives the robot to the edge when it's done.

And its party trick is one I had never seen on a pool cleaner before: an ultraviolet light on the underside that disinfects your pool surfaces while it cleans — the same UV technology used in Olympic pools and commercial aquatic centers. In my early testing, this thing is a beast, vacuuming everything from leaves to pollen right to the brim of the basket. The Clear S is the same platform minus the UV light, and it's cheaper.

So why does the Sigma keep the crown? Track record. Longevity and reliability are a huge part of my reviews, and they take months to evaluate properly. I've had years with Maytronics' commercial platform and weeks of daily runs on this Sigma; Clear is still working through my long-term testing.

The Clear UV may be the most innovative robot in my pool right now — full review coming soon — but this year, the proven, complete package is the Sigma. You can follow along with the rest of the lineup on my Clear robot reviews page.

Value and Warranty: Let's Get Real About the Price

Let's get real about the price, because the Sigma sits at the top of the range and I am not going to pretend otherwise.

Here is how I think about it. The Wave commercial robots this platform comes from cost $2,000 to $8,000-plus — and they skip the NanoFilters, the app, and the weekly timer. The Sigma gives you that commercial motor platform, adds every smart feature Maytronics makes, and backs it with a 3-year warranty — 50% longer than the standard coverage on most robots.

Owners report these commercial-motor Dolphins running strong past the ten-year mark, with parts that are cheap and easy to find. Spread across a decade of daily, hands-free cleaning, the Sigma is one of the few premium purchases I would call a bargain. This is the robot you buy once.

Certified Open Box

Love the idea of owning a Dolphin Sigma but want to score the best deal? Same here. That's why you should check out Certified Open Box or Certified Refurbished models.

These are one of the pool industry's best-kept secrets. You can get a like-new Sigma at a fraction of the price, complete with a full warranty.

Head over to ThePoolNerd.com/deals to find the best prices on open-box, refurbished, and brand-new robotic pool cleaners.

Final Verdict

So, what's my final verdict on the new Dolphin Sigma?

It's Pool Nerd Approved — and it is my pick for the best robotic pool cleaner you can buy.

Where I land is simple: the Sigma was already the most advanced robot on the market, with three commercial-grade motors, gyroscope navigation, NanoFilters, and the best app in the business. The center brush fixes the last annoyance this category had left.

Commercial power, true automation, filtration that borders on overkill, and a robot that never needs rescuing off the main drain. Yes, it costs a premium — and in my opinion, it earns every penny.

If you want the best of the best, this is it.

If you wanna keep nerding out over your pool, head over to my deals page at ThePoolNerd.com/deals, where I post the best deals on robotic pool cleaners and other pool equipment. Until next time — enjoy that pool, and I'll see you in the next one.

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Related Reading

• Best Robotic Pool Cleaners — Our overall top picks after testing 40+ robots
• Best Dolphin Pool Cleaners — Our top Dolphin picks
• Compare Every Dolphin Model — Side-by-side breakdown of all Dolphin pool cleaners
• Dolphin Premier Review — The leaf-eating king, and the Sigma's closest Dolphin rival
• Dolphin Quantum Review — ProLine features at a lower price
• Clear UV Review — The only non-Dolphin in the same conversation
• Dolphin ProLine Guide — Everything about the ProLine series
• NanoFiltration Explained — Why Gen-2 NanoFilters beat standard mesh
• All Dolphin Pool Cleaner Reviews — Every Dolphin review in one place
• All Robotic Pool Cleaner Reviews — Every robot we've tested