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.
ProLine
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
Niya Sonar
Niya Sonar Ray
Flat-bottomed above-ground and small inground pools up to 26 ft that need the floor cleaned without a cord.
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 Sigma or Niya Sonar Ray: our take
Dolphin Sigma and Niya Sonar Ray 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 Sigma is intended for inground pools, while Niya Sonar Ray is intended for inground and above-ground pools. Dolphin Sigma is rated for pools up to 50 ft; Niya Sonar Ray is rated up to 26 ft. Dolphin Sigma cleans floor, walls, and waterline; Niya Sonar Ray cleans floor. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors. Niya Sonar Ray lists Sonar navigation.
Filtration and debris
Dolphin Sigma includes Standard filter and NanoFilters; Niya Sonar Ray includes Basket. That gives Dolphin Sigma the clearer documented edge for fine silt, pollen and sand. Niya Sonar Ray has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Sigma provides a weekly timer, smartphone control, and included remote control; Niya Sonar Ray provides one-touch starts and power-supply controls. Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel, while Niya Sonar Ray uses cordless battery power. Dolphin Sigma is listed at 24.6 lb versus 7.1 lb for Niya Sonar Ray; that 17.5 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Dolphin Sigma is listed at $2,399 and Niya Sonar Ray at $199; Niya Sonar Ray is $2,200 less. Dolphin Sigma lists a 3-year warranty compared with 1 years for Niya Sonar Ray. 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 Niya Sonar Ray when it is the better fit for shoppers prioritizing the lower $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 Sigma | Niya Sonar Ray |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | YesEdge | No |
| Scrubs the waterline | YesEdge | No |
| Fine-debris filter included | YesEdge | No |
| Large-debris filter | No | YesEdge |
| Automatic scheduling | YesEdge | No |
| Smartphone app | YesEdge | No |
| Anti-tangle swivel | Yes | Not listed |
| 3-year warranty | YesEdge | No |
| No recharging between cycles | YesEdge | No |
| 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 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
- Adds gyroscope-assisted navigation
- Can start on a weekly schedule without a manual launch before every cycle
Where Niya Sonar Ray stands out
Niya Sonar Ray is the better fit for shoppers prioritizing the lower $199 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $2,200 lower
- Weighs 7.1 lb versus 24.6 lb
Dolphin Sigma vs Niya Sonar Ray 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 Sigma | Niya Sonar Ray |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. | Flat-bottomed above-ground and small inground pools up to 26 ft that need the floor cleaned without a cord. |
| Starting price | $2,399 | $199 |
| Pool type | Inground | Inground, Above-ground |
| Maximum pool length | Up to 50 ft | Up to 26 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor |
| Power | Corded | Cordless |
| Filtration | Standard filter, NanoFilters | Basket |
| Scheduling | Weekly schedule + app | One-touch start |
| App and remote | App + included remote | Power-supply controls |
| Cable | 55 ft with anti-tangle swivel | Cordless |
| Robot weight | 24.6 lb | 7.1 lb |
| Warranty | 3 years | 1 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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