Help me choose
A stronger Pool Express option
Dolphin Liberty 600 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 600
Inground and above-ground pools up to 50 ft that need floor, wall, waterline and lounge-area cleaning without a 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 600 or Dolphin M400: our take
Dolphin Liberty 600 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 600 is intended for inground and above-ground pools, while Dolphin M400 is 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.
Filtration and debris
Dolphin Liberty 600 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 600 also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Liberty 600 provides a weekly timer and smartphone control; Dolphin M400 provides smartphone control. Dolphin Liberty 600 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 600 is listed at $1,729 and Dolphin M400 at $1,599; Dolphin M400 is $130 less. Each lists a 3-year manufacturer warranty. Dolphin Liberty 600 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 600 | Dolphin M400 |
|---|---|---|
| Cleans the pool floor | Yes | Yes |
| Climbs and cleans walls | Yes | Yes |
| Scrubs the waterline | Yes | Yes |
| Fine-debris filter included | Yes | Yes |
| Large-debris filter | YesEdge | No |
| Automatic scheduling | Yes | Not listed |
| Smartphone app | Yes | Yes |
| Anti-tangle swivel | Not listed | Yes |
| 3-year warranty | Yes | Yes |
| 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 600 stands out
Dolphin Liberty 600 is the better fit for owners who value cordless handling more than automatic scheduling and continuous power.
- Includes a large-debris bin or bag for leaves
- Cleans floor, walls, waterline and lounge areas
Where Dolphin M400 stands out
Dolphin M400 is the better fit for shoppers prioritizing the lower $1,599 starting price.
- Runs from continuous plug-in power without a recharge between cycles
- Is listed $130 lower
Dolphin Liberty 600 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 600 | Dolphin M400 |
|---|---|---|
| Best fit | Inground and above-ground pools up to 50 ft that need floor, wall, waterline and lounge-area cleaning without a cord. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,729 | $1,599 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Cordless | Corded |
| Filtration | Basket, UltraFilter | Standard filter, UltraFilter |
| Scheduling | Weekly schedule + app | Not listed |
| App and remote | App control | App control |
| Cable | Cordless | 60 ft with anti-tangle swivel |
| Robot weight | 25.8 lb | Not listed |
| Warranty | 3 years | 3 years |
Consider the stronger Pool Express option
Dolphin Liberty 600 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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