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 a triple-motor cleaning system.
ProLine
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
Niya Tracker
Niya Tracker 55
Inground and above-ground pools up to 40 ft that need floor, wall and waterline cleaning without a cord, with app-selected modes.
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 Tracker 55: our take
Dolphin Sigma and Niya Tracker 55 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 Tracker 55 is intended for inground and above-ground pools. Dolphin Sigma is rated for pools up to 50 ft; Niya Tracker 55 is rated up to 40 ft. Each cleans floor, walls, and waterline, so coverage alone does not separate them. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors. Niya Tracker 55 lists 2 active brushes, Sonar navigation, and Dual drive motors.
Filtration and debris
Dolphin Sigma includes Standard filter and NanoFilters; Niya Tracker 55 includes Basket. That gives Dolphin Sigma the clearer documented edge for fine silt, pollen and sand. Niya Tracker 55 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 Tracker 55 provides one-touch starts and smartphone control. Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel, while Niya Tracker 55 uses cordless battery power. Dolphin Sigma is listed at 24.6 lb versus 19.8 lb for Niya Tracker 55; that 4.800000000000001 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Dolphin Sigma is listed at $2,399 and Niya Tracker 55 at $779; Niya Tracker 55 is $1,620 less. Dolphin Sigma lists a 3-year warranty compared with 1.5 years for Niya Tracker 55. Pool Express pick: Dolphin Sigma. Dolphin Sigma includes filtration for sand, pollen and other fine debris. Dolphin Sigma uses a triple-motor cleaning system. Choose Niya Tracker 55 when it is the better fit for shoppers prioritizing the lower $779 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 Tracker 55 |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | Yes | Yes |
| Fine-debris filter included | YesEdge | No |
| Large-debris filter | No | YesEdge |
| Automatic scheduling | YesEdge | No |
| Smartphone app | Yes | Yes |
| 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.
- Includes filtration for sand, pollen and other fine debris
- Uses a triple-motor cleaning system
- Adds gyroscope-assisted navigation
- Can start on a weekly schedule without a manual launch before every cycle
Where Niya Tracker 55 stands out
Niya Tracker 55 is the better fit for shoppers prioritizing the lower $779 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,620 lower
- Weighs 19.8 lb versus 24.6 lb
Dolphin Sigma vs Niya Tracker 55 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 Tracker 55 |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. | Inground and above-ground pools up to 40 ft that need floor, wall and waterline cleaning without a cord, with app-selected modes. |
| Starting price | $2,399 | $779 |
| Pool type | Inground | Inground, Above-ground |
| Maximum pool length | Up to 50 ft | Up to 40 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Cordless |
| Filtration | Standard filter, NanoFilters | Basket |
| Scheduling | Weekly schedule + app | One-touch start |
| App and remote | App + included remote | App control |
| Cable | 55 ft with anti-tangle swivel | Cordless |
| Robot weight | 24.6 lb | 19.8 lb |
| Warranty | 3 years | 1.5 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 a triple-motor cleaning system.
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