Help me choose
A stronger Pool Express option
Dolphin Cayman and Dolphin S400 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.
Max-Series
Dolphin Cayman
Inground and above-ground pools up to 40 ft that need floor and wall cleaning.
S-Line
Dolphin S400
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 Cayman or Dolphin S400: our take
Dolphin Cayman and Dolphin S400 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 Cayman is intended for inground and above-ground pools, while Dolphin S400 is intended for inground pools. Dolphin Cayman is rated for pools up to 40 ft; Dolphin S400 is rated up to 50 ft. Dolphin Cayman cleans floor and walls; Dolphin S400 cleans floor, walls, and waterline. Dolphin Cayman lists 1 active brush, SmartNav 2.0 navigation, and Dual 24-volt DC motors. Dolphin S400 lists 2 active brushes and CleverClean navigation.
Filtration and debris
Dolphin Cayman includes MaxBin; Dolphin S400 includes Basket and UltraFilter. Dolphin S400 has the clearer documented edge for fine silt, pollen and sand.
Controls and day-to-day ownership
Dolphin Cayman provides a weekly timer and power-supply controls; Dolphin S400 provides a weekly timer and smartphone control. Dolphin Cayman uses a 50 ft corded cable, while Dolphin S400 uses a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Cayman is listed at $1,079 and Dolphin S400 at $1,799; Dolphin Cayman is $720 less. Each lists a 2-year manufacturer warranty. Dolphin Cayman and Dolphin S400 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 Cayman | Dolphin S400 |
|---|---|---|
| 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 | Yes | Yes |
| Automatic scheduling | Yes | Yes |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | No | YesEdge |
| 3-year warranty | No | 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 Cayman stands out
Dolphin Cayman is the better fit for shoppers prioritizing the lower $1,079 starting price.
- Is listed $720 lower
- Cleans floor and walls
Where Dolphin S400 stands out
Dolphin S400 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
- Uses 2 active brushes instead of 1
- Adds smartphone control
Dolphin Cayman vs Dolphin S400 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 Cayman | Dolphin S400 |
|---|---|---|
| Best fit | Inground and above-ground pools up to 40 ft that need floor and wall cleaning. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $1,079 | $1,799 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Up to 40 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | MaxBin | Basket, UltraFilter |
| Scheduling | Weekly schedule | Weekly schedule + app |
| App and remote | Power-supply controls | App control |
| Cable | 50 ft | 60 ft with anti-tangle swivel |
| Robot weight | 14.6 lb | Not listed |
| Warranty | 2 years | 2 years |
Consider the stronger Pool Express option
Dolphin Cayman and Dolphin S400 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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