Help me choose
Our pick: Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma cleans the floor, walls and waterline instead of stopping below the tile line. Dolphin Sigma includes filtration for sand, pollen and other fine debris.
Explorer
Dolphin Explorer E40
Inground pools up to 50 ft that need floor cleaning.
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 Explorer E40 or Dolphin Sigma: our take
Dolphin Explorer E40 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. Dolphin Explorer E40 cleans floor; Dolphin Sigma cleans floor, walls, and waterline. 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 Sigma has documented included filtration—Standard filter and NanoFilters—while the other model's included media is not fully published. Dolphin Sigma has the clearer documented edge for fine silt, pollen and sand.
Controls and day-to-day ownership
Dolphin Explorer E40 provides no fully published timer, app or remote specification; Dolphin Sigma provides a weekly timer, smartphone control, and included remote control.
Price, warranty and the decision
Dolphin Explorer E40 is listed at $1,599 and Dolphin Sigma at $2,399; Dolphin Explorer E40 is $800 less. Each lists a 3-year manufacturer warranty. Pool Express pick: Dolphin Sigma. Dolphin Sigma cleans the floor, walls and waterline instead of stopping below the tile line. Dolphin Sigma includes filtration for sand, pollen and other fine debris. Choose Dolphin Explorer E40 when it is the better fit for shoppers prioritizing the lower $1,599 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 Explorer E40 | Dolphin Sigma |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | No | YesEdge |
| Scrubs the waterline | No | YesEdge |
| Fine-debris filter included | No | YesEdge |
| Large-debris filter | No | No |
| Automatic scheduling | Not listed | Yes |
| Smartphone app | Not listed | Yes |
| Anti-tangle swivel | Not listed | Yes |
| 3-year warranty | Yes | Yes |
| No recharging between cycles | Not listed | 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 Explorer E40 stands out
Dolphin Explorer E40 is the better fit for shoppers prioritizing the lower $1,599 starting price.
- Is listed $800 lower
- Cleans the pool floor
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.
- Cleans the floor, walls and waterline instead of stopping below the tile line
- Includes filtration for sand, pollen and other fine debris
- Has documented smartphone control
Dolphin Explorer E40 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 Explorer E40 | Dolphin Sigma |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor cleaning. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,599 | $2,399 |
| Pool type | Inground | Inground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor | Floor, Walls, Waterline |
| Power | Not listed | Corded |
| Filtration | Not listed | Standard filter, NanoFilters |
| Scheduling | Not listed | Weekly schedule + app |
| App and remote | Not listed | App + included remote |
| Cable | Not listed | 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 cleans the floor, walls and waterline instead of stopping below the tile line. Dolphin Sigma includes filtration for sand, pollen and other fine debris.
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