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 uses a triple-motor cleaning system.
Liberty
Dolphin Liberty 300
Inground and above-ground pools that need floor and wall cleaning, with fine debris, without a power cord.
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 Liberty 300 or Dolphin Sigma: our take
Dolphin Liberty 300 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 Liberty 300 is intended for inground and above-ground pools, while Dolphin Sigma is 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. Dolphin Liberty 300 cleans floor and walls; Dolphin Sigma cleans floor, walls, and waterline. Dolphin Liberty 300 lists Dual DC motors. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors.
Filtration and debris
Dolphin Liberty 300 includes Basket and UltraFilter; Dolphin Sigma includes Standard filter and NanoFilters. Both have documented fine-debris media, so basket capacity and ease of cleaning matter more than fine-particle capability. Dolphin Liberty 300 also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Liberty 300 provides no fully published timer, app or remote specification; Dolphin Sigma provides a weekly timer, smartphone control, and included remote control. Dolphin Liberty 300 uses cordless battery power, while Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Liberty 300 is listed at $1,099 and Dolphin Sigma at $2,399; Dolphin Liberty 300 is $1,300 less. Dolphin Liberty 300 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 uses a triple-motor cleaning system. Choose Dolphin Liberty 300 when it is the better fit for shoppers prioritizing the lower $1,099 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 Liberty 300 | Dolphin Sigma |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | No | YesEdge |
| Fine-debris filter included | Yes | Yes |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | Not listed | Yes |
| Smartphone app | Not listed | Yes |
| Anti-tangle swivel | Not listed | Yes |
| 3-year warranty | No | YesEdge |
| No recharging between cycles | No | YesEdge |
| 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 Liberty 300 stands out
Dolphin Liberty 300 is the better fit for shoppers prioritizing the lower $1,099 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,300 lower
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
- Uses a triple-motor cleaning system
- Has documented smartphone control
- Carries a 3-year warranty instead of 2 years
Dolphin Liberty 300 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 Liberty 300 | Dolphin Sigma |
|---|---|---|
| Best fit | Inground and above-ground pools that need floor and wall cleaning, with fine debris, without a power cord. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,099 | $2,399 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Not listed | Up to 50 ft |
| Cleaning coverage | Floor, Walls | Floor, Walls, Waterline |
| Power | Cordless | Corded |
| Filtration | Basket, UltraFilter | Standard filter, NanoFilters |
| Scheduling | Not listed | Weekly schedule + app |
| App and remote | Not listed | App + included remote |
| Cable | Cordless | 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 cleans the floor, walls and waterline instead of stopping below the tile line. Dolphin Sigma uses a triple-motor cleaning system.
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