Help me choose
A stronger Pool Express option
Dolphin M550 and Dolphin Nautilus EON 100 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 M550
Inground pools up to 50 ft that need floor, wall and waterline cleaning with app control, Pick-Up and a caddy.
EON
Dolphin Nautilus EON 100
Inground and above-ground pools up to 50 ft with steps, benches or tanning ledges that need whole-pool cordless 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 M550 or Dolphin Nautilus EON 100: our take
Dolphin M550 and Dolphin Nautilus EON 100 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 M550 is intended for inground pools, while Dolphin Nautilus EON 100 is intended for inground and above-ground pools. Both are rated for pools up to 50 ft. Each cleans floor, walls, and waterline, so coverage alone does not separate them. Dolphin M550 lists 2 active brushes and CleverClean navigation. Dolphin Nautilus EON 100 lists 2 active brushes and SmartMap navigation.
Filtration and debris
Dolphin M550 includes Basket and UltraFilter; Dolphin Nautilus EON 100 includes Basket. That gives Dolphin M550 the clearer documented edge for fine silt, pollen and sand.
Controls and day-to-day ownership
Both models provide a weekly timer and smartphone control. Dolphin M550 uses continuous corded power, while Dolphin Nautilus EON 100 uses cordless battery power. Dolphin M550 is listed at 22.6 lb versus 22.1 lb for Dolphin Nautilus EON 100; that 0.5 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Dolphin M550 is listed at $1,999 and Dolphin Nautilus EON 100 at $899; Dolphin Nautilus EON 100 is $1,100 less. Dolphin M550 lists a 3-year warranty compared with 1 years for Dolphin Nautilus EON 100. Dolphin M550 and Dolphin Nautilus EON 100 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 M550 | Dolphin Nautilus EON 100 |
|---|---|---|
| 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 | Yes | Yes |
| Automatic scheduling | Yes | Yes |
| Smartphone app | Yes | Yes |
| Anti-tangle swivel | Yes | Not listed |
| 3-year warranty | YesEdge | No |
| No recharging between cycles | YesEdge | No |
| 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 M550 stands out
Dolphin M550 is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning with app control, Pick-Up and a caddy.
- Includes filtration for sand, pollen and other fine debris
- Carries a 3-year warranty instead of 1 years
- Runs from continuous plug-in power without a recharge between cycles
Where Dolphin Nautilus EON 100 stands out
Dolphin Nautilus EON 100 is the better fit for shoppers prioritizing the lower $899 starting price.
- Is listed $1,100 lower
- Weighs 22.1 lb versus 22.6 lb
Dolphin M550 vs Dolphin Nautilus EON 100 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 M550 | Dolphin Nautilus EON 100 |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning with app control, Pick-Up and a caddy. | Inground and above-ground pools up to 50 ft with steps, benches or tanning ledges that need whole-pool cordless cleaning. |
| Starting price | $1,999 | $899 |
| Pool type | Inground | Inground, Above-ground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Cordless |
| Filtration | Basket, UltraFilter | Basket |
| Scheduling | Weekly schedule + app | Weekly schedule + app |
| App and remote | App control | App control |
| Cable | Not listed | Cordless |
| Robot weight | 22.6 lb | 22.1 lb |
| Warranty | 3 years | 1 years |
Consider the stronger Pool Express option
Dolphin M550 and Dolphin Nautilus EON 100 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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