Help me choose
Our pick: Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma includes a 55 ft cable with anti-tangle swivel. Dolphin Sigma's documented advantages include standard filters and NanoFilters.
M-Line
Dolphin M600
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
ProLine
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
Why Dolphin Sigma is our pick
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
$2,399
Buy Dolphin SigmaDolphin M600 or Dolphin Sigma: our take
Dolphin M600 and Dolphin Sigma are compared on pool fit, cleaning reach, debris handling, controls and ownership details. The recommendation is based on the job the robot must do—not a simple feature count.
Pool fit and cleaning reach
Both robots are intended for inground pools. Both are rated for pools up to 50 ft. Each cleans floor, walls, and waterline, so coverage alone does not separate them. Dolphin Sigma's documented cleaning system includes 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors.
Filtration and debris
Dolphin M600 includes Basket and UltraFilter; Dolphin Sigma includes Standard filter and NanoFilters. Both have documented fine-debris media, so basket capacity and ease of cleaning matter more than fine-particle capability. Dolphin M600 also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Both models provide a weekly timer, smartphone control, and included remote control. Dolphin M600 uses a 60 ft corded cable with an anti-tangle swivel, while Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin M600 is listed at $1,999 and Dolphin Sigma at $2,399; Dolphin M600 is $400 less. Each lists a 3-year manufacturer warranty. Pool Express pick: Dolphin Sigma. Dolphin Sigma includes a 55 ft cable with anti-tangle swivel. Dolphin Sigma's documented advantages include standard filters and NanoFilters. Choose Dolphin M600 when it is the better fit for shoppers prioritizing the lower $1,999 starting price.
Feature check: what each robot actually has
A green check means the feature is documented as included. A red X means it is documented as absent. A dash means the source does not make the feature clear.
| Feature | Dolphin M600 | Dolphin Sigma |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | Yes | Yes |
| Fine-debris filter included | Yes | Yes |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | Yes | Yes |
| Smartphone app | Yes | Yes |
| Anti-tangle swivel | Yes | Yes |
| 3-year warranty | Yes | Yes |
| No recharging between cycles | Yes | Yes |
| Built-in UV-C water treatment | No | No |
Unknown is not treated as “no.” Specifications come from the product pages, current catalog records and manufacturer material collected for this site.
Where Dolphin M600 stands out
Dolphin M600 is the better fit for shoppers prioritizing the lower $1,999 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $400 lower
Where Dolphin Sigma stands out
Dolphin Sigma is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
- 55 ft cable with anti-tangle swivel
- Standard filters and NanoFilters
Dolphin M600 vs Dolphin Sigma specifications
Use pool fit first. Price and app control do not make up for a robot that cannot cover the length or surfaces you need cleaned.
| Specification | Dolphin M600 | Dolphin Sigma |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,999 | $2,399 |
| Pool type | Inground | Inground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket, UltraFilter | Standard filter, NanoFilters |
| Scheduling | Weekly schedule + app | Weekly schedule + app |
| App and remote | App + included remote | App + included remote |
| Cable | 60 ft with anti-tangle swivel | 55 ft with anti-tangle swivel |
| Robot weight | Not listed | 24.6 lb |
| Warranty | 3 years | 3 years |
Choose Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma includes a 55 ft cable with anti-tangle swivel. Dolphin Sigma's documented advantages include standard filters and NanoFilters.
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