Help me choose
Our pick: Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma includes filtration for sand, pollen and other fine debris. Dolphin Sigma uses 2 active brushes instead of 1.
Proteus
Dolphin Proteus DX4
Inground pools that need floor, wall and waterline 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 Proteus DX4 or Dolphin Sigma: our take
Dolphin Proteus DX4 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. Dolphin Sigma has a published maximum pool length of 50 ft; the other model does not have a verified length in our source material. Each cleans floor, walls, and waterline, so coverage alone does not separate them. Dolphin Proteus DX4 lists 1 active brush. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors.
Filtration and debris
Dolphin Proteus DX4 includes Basket; Dolphin Sigma includes Standard filter and NanoFilters. Dolphin Sigma has the clearer documented edge for fine silt, pollen and sand. Dolphin Proteus DX4 also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Proteus DX4 provides a weekly timer and power-supply controls; Dolphin Sigma provides a weekly timer, smartphone control, and included remote control. Dolphin Proteus DX4 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 Proteus DX4 is listed at $1,199 and Dolphin Sigma at $2,399; Dolphin Proteus DX4 is $1,200 less. Dolphin Proteus DX4 lists a 2-year warranty compared with 3 years for Dolphin Sigma. Pool Express pick: Dolphin Sigma. Dolphin Sigma includes filtration for sand, pollen and other fine debris. Dolphin Sigma uses 2 active brushes instead of 1. Choose Dolphin Proteus DX4 when it is the better fit for shoppers prioritizing the lower $1,199 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 Proteus DX4 | Dolphin Sigma |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | Yes | Yes |
| Fine-debris filter included | No | YesEdge |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | Yes | Yes |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | Yes | Yes |
| 3-year warranty | No | YesEdge |
| 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 Proteus DX4 stands out
Dolphin Proteus DX4 is the better fit for shoppers prioritizing the lower $1,199 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,200 lower
Where Dolphin Sigma stands out
Dolphin Sigma is the better fit for owners who put smartphone control first.
- Includes filtration for sand, pollen and other fine debris
- Uses 2 active brushes instead of 1
- Adds smartphone control
- Carries a 3-year warranty instead of 2 years
Dolphin Proteus DX4 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 Proteus DX4 | Dolphin Sigma |
|---|---|---|
| Best fit | Inground pools that need floor, wall and waterline cleaning. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,199 | $2,399 |
| Pool type | Inground | Inground |
| Maximum pool length | Not listed | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket | Standard filter, NanoFilters |
| Scheduling | Weekly schedule | Weekly schedule + app |
| App and remote | Power-supply controls | App + included remote |
| Cable | 60 ft with anti-tangle swivel | 55 ft with anti-tangle swivel |
| Robot weight | Not listed | 24.6 lb |
| Warranty | 2 years | 3 years |
Choose Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma includes filtration for sand, pollen and other fine debris. Dolphin Sigma uses 2 active brushes instead of 1.
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