Help me choose
A stronger Pool Express option
Dolphin Active Solo and Dolphin M400 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.
Active
Dolphin Active Solo
Inground and above-ground pools up to 33 ft that need floor and wall cleaning at the lowest Active-series price.
M-Line
Dolphin M400
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
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 Active Solo or Dolphin M400: our take
Dolphin Active Solo and Dolphin M400 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 Active Solo is intended for inground and above-ground pools, while Dolphin M400 is intended for inground pools. Dolphin Active Solo is rated for pools up to 33 ft; Dolphin M400 is rated up to 50 ft. Dolphin Active Solo cleans floor and walls; Dolphin M400 cleans floor, walls, and waterline. Dolphin Active Solo's documented cleaning system includes 1 active brush and CleverClean navigation.
Filtration and debris
Dolphin Active Solo includes Basket; Dolphin M400 includes Standard filter and UltraFilter. Dolphin M400 has the clearer documented edge for fine silt, pollen and sand. Dolphin Active Solo also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Active Solo provides one-touch starts and power-supply controls; Dolphin M400 provides smartphone control. Dolphin Active Solo uses continuous corded power, while Dolphin M400 uses a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Active Solo is listed at $599 and Dolphin M400 at $1,599; Dolphin Active Solo is $1,000 less. Dolphin Active Solo lists a 2-year warranty compared with 3 years for Dolphin M400. Dolphin Active Solo and Dolphin M400 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 Active Solo | Dolphin M400 |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | No | YesEdge |
| Fine-debris filter included | No | YesEdge |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | No | Not listed |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | No | YesEdge |
| 3-year warranty | No | YesEdge |
| 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 Active Solo stands out
Dolphin Active Solo is the better fit for shoppers prioritizing the lower $599 starting price.
- Includes a large-debris bin or bag for leaves
- Is listed $1,000 lower
Where Dolphin M400 stands out
Dolphin M400 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 smartphone control
- Uses an anti-tangle swivel cable
Dolphin Active Solo vs Dolphin M400 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 Active Solo | Dolphin M400 |
|---|---|---|
| Best fit | Inground and above-ground pools up to 33 ft that need floor and wall cleaning at the lowest Active-series price. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $599 | $1,599 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Up to 33 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket | Standard filter, UltraFilter |
| Scheduling | One-touch start | Not listed |
| App and remote | Power-supply controls | App control |
| Cable | Not listed | 60 ft with anti-tangle swivel |
| Robot weight | 14.6 lb | Not listed |
| Warranty | 2 years | 3 years |
Consider the stronger Pool Express option
Dolphin Active Solo and Dolphin M400 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.
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