Help me choose
A stronger Pool Express option
Dolphin Liberty 300 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.
Liberty
Dolphin Liberty 300
Inground and above-ground pools that need floor and wall cleaning, with fine debris, without a power cord.
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 Liberty 300 or Dolphin M400: our take
Dolphin Liberty 300 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 Liberty 300 is intended for inground and above-ground pools, while Dolphin M400 is intended for inground pools. Dolphin M400 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 M400 cleans floor, walls, and waterline. Dolphin Liberty 300's documented cleaning system includes Dual DC motors.
Filtration and debris
Dolphin Liberty 300 includes Basket and UltraFilter; Dolphin M400 includes Standard filter and UltraFilter. 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 M400 provides smartphone control. Dolphin Liberty 300 uses cordless battery power, while Dolphin M400 uses a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Liberty 300 is listed at $1,099 and Dolphin M400 at $1,599; Dolphin Liberty 300 is $500 less. Dolphin Liberty 300 lists a 2-year warranty compared with 3 years for Dolphin M400. Dolphin Liberty 300 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 Liberty 300 | Dolphin M400 |
|---|---|---|
| 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 | Not listed |
| 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 $500 lower
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.
- Cleans the floor, walls and waterline instead of stopping below the tile line
- Has documented smartphone control
- Carries a 3-year warranty instead of 2 years
- Runs from continuous plug-in power without a recharge between cycles
Dolphin Liberty 300 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 Liberty 300 | Dolphin M400 |
|---|---|---|
| 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 | $1,599 |
| 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, UltraFilter |
| Scheduling | Not listed | Not listed |
| App and remote | Not listed | App control |
| Cable | Cordless | 60 ft with anti-tangle swivel |
| Robot weight | Not listed | Not listed |
| Warranty | 2 years | 3 years |
Consider the stronger Pool Express option
Dolphin Liberty 300 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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