Help me choose
A stronger Pool Express option
Dolphin Nautilus Pool Up and Dolphin T55i 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.
Nautilus
Dolphin Nautilus Pool Up
Inground and above-ground pools up to 30 ft that need floor and wall cleaning, with heavy leaves.
T-Line
Dolphin T55i
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 Nautilus Pool Up or Dolphin T55i: our take
Dolphin Nautilus Pool Up and Dolphin T55i 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 Nautilus Pool Up is intended for inground and above-ground pools, while Dolphin T55i is intended for inground pools. Dolphin Nautilus Pool Up is rated for pools up to 30 ft; Dolphin T55i is rated up to 50 ft. Dolphin Nautilus Pool Up cleans floor and walls; Dolphin T55i cleans floor, walls, and waterline. Dolphin Nautilus Pool Up's documented cleaning system includes 1 active brush.
Filtration and debris
Dolphin Nautilus Pool Up includes Oversized leaf bag; Dolphin T55i includes Basket and UltraFilter. Dolphin T55i has the clearer documented edge for fine silt, pollen and sand.
Controls and day-to-day ownership
Dolphin Nautilus Pool Up provides one-touch starts and power-supply controls; Dolphin T55i provides a weekly timer, smartphone control, and included remote control. Dolphin Nautilus Pool Up uses a 40 ft corded cable, while Dolphin T55i uses a 60 ft corded cable with an anti-tangle swivel.
Price, warranty and the decision
Dolphin Nautilus Pool Up is listed at $499 and Dolphin T55i at $1,699; Dolphin Nautilus Pool Up is $1,200 less. Each lists a 2-year manufacturer warranty. Dolphin Nautilus Pool Up and Dolphin T55i 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 Nautilus Pool Up | Dolphin T55i |
|---|---|---|
| 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 | No | YesEdge |
| Smartphone app | No | YesEdge |
| Anti-tangle swivel | Not listed | Yes |
| 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 Nautilus Pool Up stands out
Dolphin Nautilus Pool Up is the better fit for shoppers prioritizing the lower $499 starting price.
- Includes an oversized leaf bag for bulky seasonal debris
- Is listed $1,200 lower
Where Dolphin T55i stands out
Dolphin T55i 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
- Can start on a weekly schedule without a manual launch before every cycle
- Adds smartphone control
Dolphin Nautilus Pool Up vs Dolphin T55i 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 Nautilus Pool Up | Dolphin T55i |
|---|---|---|
| Best fit | Inground and above-ground pools up to 30 ft that need floor and wall cleaning, with heavy leaves. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | $499 | $1,699 |
| Pool type | Inground, Above-ground | Inground |
| Maximum pool length | Up to 30 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Oversized leaf bag | Basket, UltraFilter |
| Scheduling | One-touch start | Weekly schedule + app |
| App and remote | Power-supply controls | App + included remote |
| Cable | 40 ft | 60 ft with anti-tangle swivel |
| Robot weight | 18 lb | Not listed |
| Warranty | 2 years | 2 years |
Consider the stronger Pool Express option
Dolphin Nautilus Pool Up and Dolphin T55i 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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