Dolphin M600 vs Sigma: Features, Filtration and Price Compared

By John, Dolphin pool cleaner repair technician at Pelican Shops Morris Plains · Updated October 29, 2026

The Dolphin M600 and Sigma are both corded cleaners for inground pools, and both offer features like app control and waterline cleaning. That can make them sound similar when you are reading product descriptions. The differences become clearer when you look at the brushes, filtration, cleaning modes, included accessories and actual asking price.

I am John, a Dolphin pool cleaner repair technician at Pelican Shops Morris Plains. When I compare robots, I look at the equipment and what it means for the person who will use, clean and maintain the machine. Here is how these two models compare.

This article compares the equipment and specifications of both cleaners alongside our comparison chart. We sell the M600 at Pelican, and the pricing below distinguishes our 2026 MSRP reference figures from an advertised online selling price.

Dolphin M600 vs Sigma: side-by-side specifications

The manufacturer pages linked here identify the M600 as 99996650-US and the Sigma as 99991036-SPLI. The table below brings the specifications, included equipment and pricing together in one place.

Dolphin M600 and Sigma specifications and features

Sources: Dolphin M600 specifications, Dolphin Sigma specifications and our Dolphin comparison chart.

Active brush: what is actually different?

One detail I want customers to understand is the difference between a cleaner having normal brushes and having an active scrubber brush. These are different things.

Dolphin explains that an active brush on certain models rotates faster than the robot travels, adding brushing action to help loosen debris. The M600 has an active brush. The Sigma does not

You may see the words “active scrubbing” in general descriptions of the Sigma, including introductory wording on Dolphin’s own page. That wording is confusing because the specific “Active Brush” field says “No.” When I compare the actual feature, I use that technical field, which also agrees with our chart.

The important distinction is the mechanism itself. A brush rotating against the surface and an active scrubber are not the same feature, even when both descriptions use the word “scrubbing.” 

Basically, The M600 will have a brush that spins a lot faster for better scrubbing, the Sigma does not have a similar brush. 

Read Dolphin’s explanation of its brush types.

Suction rate: 5,000 GPH vs 4,500 GPH

The M600 has a suction rate of 5,000 gallons per hour, compared with 4,500 GPH for the Sigma.

That is 500 GPH more rated flow, or about an 11% increase. I consider that an advantage, but I would not tell you it means exactly 11% more dirt gets removed. Flow rate is one part of cleaning performance. Brushing, filtration, movement speed and the condition of the filters also matter.

This is why I compare the whole machine. The M600’s appeal comes from the combination of its features, rather than a single number.

Does the Sigma have special “commercial-grade” motors?

As a repair technician, I look at the replacement parts behind a claim like that. The Sigma and M400 share the same motor-unit part number. The M400 is a residential Dolphin cleaner, so describing the Sigma’s motor unit as a special commercial upgrade over that residential model does not reflect a truthful statement based on dolphins stats. 

Dolphin’s own motor-replacement support page also groups the Sigma with the M400/M500 family. That supports the shared part number

More importantly, Dolphin does not describe the Sigma’s motors as “commercial-grade” on its product page. That language comes from reseller marketing which you have to be careful of. Maytronics lists the Sigma in its residential range and identifies the Wave line as its commercial-cleaner, where it discusses equipment for hotels, resorts and other commercial pools.

Sources: Dolphin’s motor-replacement support page, Sigma manufacturer specifications and Maytronics’ commercial cleaner lineup. The matching motor-unit part number is based on our repair-parts knowledge.

Gyroscope technology is not exclusive to the Sigma

Do not let a description of the Sigma’s gyroscope make you think it is the only Dolphin with that technology. Gyroscope-based navigation is used in every Dolphin; it is not a Sigma-exclusive advantage.

The M600’s top-loading basket is easier to clean out and overall means less parts internally

Both robots give you access to their filters from the top which is a positive trait, but they do not use the same filter design. The M600 has a top-loading basket, while the Sigma uses cartridges. 

From my experience working on these cleaners, the M600’s basket is much easier to remove, empty and rinse out. Filter cleaning is a regular part of ownership, so this is something you will appreciate repeatedly, not just when you first unpack the robot.

The M600 has fewer internal parts overall than the Sigma. That simpler internal design means fewer individual parts to worry about maintaining or replacing. Ease of emptying the basket is one benefit; fewer parts inside the cleaner is a separate ownership consideration. Less parts is a good thing long term, less that gets worn down over time. 

Both models include fine and ultra-fine filtration in the packages compared here. However the M600 also comes with an additional Filter layer you can use to get an added layer of filtration on top of the fine or ultra fine filters. 

The M600 also has a full-filter indicator. That is another useful feature for keeping up with routine maintenance.

More control over the cleaning routine

The M600 can clean just the floor when you want it to. You do not have to send it up the walls and have waterline scrubbing every time. If the dirt is mainly on the bottom, you can choose floor-only cleaning. Notably the Sigma does not have this feature. 

Waterline cleaning and getting the robot out

Both cleaners are designed to clean the waterline. Our chart highlights the M600’s jet-assisted system, which is another part of its design worth understanding. Dolphin describes PowerStream as using multidirectional water jets to help maintain grip and movement along the waterline

We also list Pick-Up Mode for the M600 in our chart. Dolphin describes this feature as bringing the cleaner to the pool edge to assist removal. The included caddy helps with transport and storage once it is out. Those are practical ownership features that deserve attention alongside cleaning specifications.

Read Dolphin’s PowerStream explanation and Pick-Up Mode explanation. 

Compare the price and the support behind it

On our comparison page, I talk about how heavily certain models, including the Sigma, are promoted online. Here, we have laid out the equipment, pricing and service benefits together so you can see what each model offers. Being recommended repeatedly does not make a robot the best equipped, and a large advertised discount does not automatically make it the best value.

MSRP and the advertised selling price are different numbers

Our 2026 dealer pricing and comparison chart list the M600 at $2,149 MSRP and the Sigma at $1,599 MSRP. At those reference prices, the Sigma is $550 less expensive. That is a real price difference, and it belongs in the comparison.

However, the Sigma is also advertised online and is only being sold at $2,399. For example, this online retailer’s listing shows that price. At $2,399, the Sigma is $800 above our $1,599 MSRP reference and $250 above the M600’s $2,149 MSRP. 

The M600 also often qualifies for seasonal rebates, while the Sigma does not. When an eligible promotion is available, a rebate can reduce the M600’s effective cost further. Amounts, qualifying purchase dates and redemption requirements vary by promotion. The $250 price difference discussed here is before any applicable M600 rebate.

That changes the question. At the lower reference price, you are weighing a $550 saving against the differences in equipment. At the $2,399 advertised price, you are paying $250 more than the M600 reference price while the active brush, floor-only option and included caddy remain on the M600 side of the table.

A higher asking price does not add those features to the Sigma. The feature table shows the equipment differences, and our service details below explain what comes with an eligible Pelican purchase.

At Pelican, we have our own Dolphin repair technicians. On eligible purchases, our enhanced warranty program includes covered repair labor during the manufacturer warranty period, plus shipping to and from us for the first two qualifying repairs in the mainland United States. 

What the comparison leaves you with

The two cleaners share several headline features, but the equipment is not identical. The M600 adds an active brush, higher flow, a basket that is easier to clean out, floor-only cleaning, a filter indicator, retrieval assistance and an included caddy. The Sigma should only be considered at the true MSRP. do not pay $800 over MSRP. At the prices compared here, the M600’s $2,149 MSRP is $250 below the Sigma’s $2,399 advertised online price making it instantly a better value. Our M600 product pagehas ordering information and details of the package we offer.

If your aim was to spend closer to that $1599 price area we would suggest looking at the M400 over the Sigma. Same overall design but it has the active brush and our enhanced warranty coverage when bought from us. 

To order through Pelican or get help matching a cleaner to your pool, call me and our robot team at 973-313-4424. Tell us your pool size, surface, common debris and the models you are considering. We can walk through the differences with you and explain what you are getting.

See our Dolphin M600 or view our full Dolphin comparison chart.

Updated October 29, 2026. Prices, rebates and bundles can change. This comparison describes the listed equipment, pricing and ownership features.