Help me choose
A stronger Pool Express option
Dolphin M400 and Dolphin Proteus DX5i are compared feature by feature below. For a stronger Pool Express option, consider Dolphin Quantum. Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
M-Line
Dolphin M400
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
Proteus
Dolphin Proteus DX5i
Inground pools up to 50 ft that need floor, wall and waterline cleaning.
What we recommend instead
Dolphin Quantum
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
$1,649
Buy Dolphin QuantumDolphin M400 or Dolphin Proteus DX5i: our take
Dolphin M400 and Dolphin Proteus DX5i 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
Both robots are intended for inground pools. Both are rated for pools up to 50 ft. Each cleans floor, walls, and waterline, so coverage alone does not separate them. Dolphin Proteus DX5i's documented cleaning system includes 1 active brush.
Filtration and debris
Dolphin M400 includes Standard filter and UltraFilter; Dolphin Proteus DX5i includes Basket. That gives Dolphin M400 the clearer documented edge for fine silt, pollen and sand. Dolphin Proteus DX5i has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Both models provide smartphone control. Both use a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin M400 is listed at $1,599 and Dolphin Proteus DX5i at $1,299; Dolphin Proteus DX5i is $300 less. Dolphin M400 lists a 3-year warranty compared with 2 years for Dolphin Proteus DX5i. Dolphin M400 and Dolphin Proteus DX5i each have a specific fit, but neither is the Pool Express pick for this job. Our better alternative is Dolphin Quantum. Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
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 M400 | Dolphin Proteus DX5i |
|---|---|---|
| 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 | Not listed | Not listed |
| Smartphone app | Yes | Yes |
| Anti-tangle swivel | Yes | Yes |
| 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 M400 stands out
Dolphin M400 is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
- Includes filtration for sand, pollen and other fine debris
- Carries a 3-year warranty instead of 2 years
Where Dolphin Proteus DX5i stands out
Dolphin Proteus DX5i is the better fit for shoppers prioritizing the lower $1,299 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $300 lower
Dolphin M400 vs Dolphin Proteus DX5i 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 M400 | Dolphin Proteus DX5i |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. | Inground pools up to 50 ft that need floor, wall and waterline cleaning. |
| Starting price | $1,599 | $1,299 |
| Pool type | Inground | Inground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Standard filter, UltraFilter | Basket |
| Scheduling | Not listed | Not listed |
| App and remote | App control | App control |
| Cable | 60 ft with anti-tangle swivel | 60 ft with anti-tangle swivel |
| Robot weight | Not listed | Not listed |
| Warranty | 3 years | 2 years |
Consider the stronger Pool Express option
Dolphin M400 and Dolphin Proteus DX5i are compared feature by feature below. For a stronger Pool Express option, consider Dolphin Quantum. Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
More robotic pool cleaner comparisons
Keep comparing without rebuilding the same specification table yourself.
Clear UV vs Clear S
Pool Express pick: Clear UV
Dolphin Quantum vs Clear S
Pool Express pick: Dolphin Quantum
Dolphin Premier vs Dolphin Sigma
Pool Express pick: Dolphin Premier
Dolphin Premier vs Dolphin Quantum
Pool Express pick: Dolphin Quantum
Dolphin Sigma vs Dolphin Quantum
Pool Express pick: Dolphin Quantum
Dolphin Cayman vs Dolphin Escape
Pool Express pick: Dolphin Cayman