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.
Echo
Dolphin Echo
Inground and above-ground pools up to 33 ft that need floor and wall cleaning with the least fuss.
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 Echo or Dolphin Sigma: our take
Dolphin Echo 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
Dolphin Echo is intended for inground and above-ground pools, while Dolphin Sigma is intended for inground pools. Dolphin Echo is rated for pools up to 33 ft; Dolphin Sigma is rated up to 50 ft. Dolphin Echo cleans floor and walls; Dolphin Sigma cleans floor, walls, and waterline. Dolphin Echo lists 1 active brush and CleverClean navigation. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors.
Filtration and debris
Dolphin Echo includes Basket; Dolphin Sigma includes Standard filter and NanoFilters. Dolphin Sigma has the clearer documented edge for fine silt, pollen and sand. Dolphin Echo also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Echo provides one-touch starts and power-supply controls; Dolphin Sigma provides a weekly timer, smartphone control, and included remote control. Dolphin Echo uses continuous corded power, while Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel. Dolphin Echo is listed at 14.8 lb versus 24.6 lb for Dolphin Sigma; that 9.8 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Dolphin Echo is listed at $749 and Dolphin Sigma at $2,399; Dolphin Echo is $1,650 less. Dolphin Echo lists a 2-year warranty compared with 3 years for Dolphin Sigma. 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 Echo when it is the better fit for shoppers prioritizing the lower $749 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 Echo | Dolphin Sigma |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | No | YesEdge |
| Fine-debris filter included | No | YesEdge |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | No | YesEdge |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | No | YesEdge |
| 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 Echo stands out
Dolphin Echo is the better fit for shoppers prioritizing the lower $749 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,650 lower
- Weighs 14.8 lb versus 24.6 lb
Where Dolphin Sigma stands out
Dolphin Sigma is the better fit for pools up to 50 ft.
- Cleans the floor, walls and waterline instead of stopping below the tile line
- Includes filtration for sand, pollen and other fine debris
- Uses 2 active brushes instead of 1
- Adds gyroscope-assisted navigation
Dolphin Echo 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 Echo | Dolphin Sigma |
|---|---|---|
| Best fit | Inground and above-ground pools up to 33 ft that need floor and wall cleaning with the least fuss. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $749 | $2,399 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Up to 33 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket | Standard filter, NanoFilters |
| Scheduling | One-touch start | Weekly schedule + app |
| App and remote | Power-supply controls | App + included remote |
| Cable | Not listed | 55 ft with anti-tangle swivel |
| Robot weight | 14.8 lb | 24.6 lb |
| Warranty | 2 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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