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 2 active brushes instead of 1.
ProLine
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
T-Line
Dolphin T25
Inground and above-ground pools up to 33 ft that need floor and wall 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 Sigma or Dolphin T25: our take
Dolphin Sigma and Dolphin T25 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 Dolphin T25 is intended for inground and above-ground pools. Dolphin Sigma is rated for pools up to 50 ft; Dolphin T25 is rated up to 33 ft. Dolphin Sigma cleans floor, walls, and waterline; Dolphin T25 cleans floor and walls. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors. Dolphin T25 lists 1 active brush.
Filtration and debris
Dolphin Sigma includes Standard filter and NanoFilters; Dolphin T25 includes Basket and UltraFilter. Both have documented fine-debris media, so basket capacity and ease of cleaning matter more than fine-particle capability. Dolphin T25 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; Dolphin T25 provides a weekly timer and power-supply controls. Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel, while Dolphin T25 uses a 50 ft corded cable. Dolphin Sigma is listed at 24.6 lb versus 15 lb for Dolphin T25; that 9.600000000000001 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Dolphin Sigma is listed at $2,399 and Dolphin T25 at $849; Dolphin T25 is $1,550 less. Dolphin Sigma lists a 3-year warranty compared with 2 years for Dolphin T25. Pool Express pick: Dolphin Sigma. Dolphin Sigma cleans the floor, walls and waterline instead of stopping below the tile line. Dolphin Sigma uses 2 active brushes instead of 1. Choose Dolphin T25 when it is the better fit for shoppers prioritizing the lower $849 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 | Dolphin T25 |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | YesEdge | No |
| Fine-debris filter included | Yes | Yes |
| Large-debris filter | No | YesEdge |
| Automatic scheduling | Yes | Yes |
| Smartphone app | YesEdge | No |
| Anti-tangle swivel | Yes | Not listed |
| 3-year warranty | YesEdge | No |
| 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 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
- Uses 2 active brushes instead of 1
- Adds smartphone control
- Carries a 3-year warranty instead of 2 years
Where Dolphin T25 stands out
Dolphin T25 is the better fit for shoppers prioritizing the lower $849 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,550 lower
- Weighs 15 lb versus 24.6 lb
Dolphin Sigma vs Dolphin T25 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 | Dolphin T25 |
|---|---|---|
| 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 33 ft that need floor and wall cleaning, with fine debris. |
| Starting price | $2,399 | $849 |
| Pool type | Inground | Inground, Above-ground |
| Maximum pool length | Up to 50 ft | Up to 33 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls |
| Power | Corded | Corded |
| Filtration | Standard filter, NanoFilters | Basket, UltraFilter |
| Scheduling | Weekly schedule + app | Weekly schedule |
| App and remote | App + included remote | Power-supply controls |
| Cable | 55 ft with anti-tangle swivel | 50 ft |
| Robot weight | 24.6 lb | 15 lb |
| Warranty | 3 years | 2 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 2 active brushes instead of 1.
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