Help me choose
Our pick: Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma adds gyroscope-assisted navigation. Dolphin Sigma weighs 24.6 lb versus 26.7 lb.
Oasis
Dolphin Oasis Z5i
Inground pools up to 50 ft that need floor, wall and waterline cleaning with app scheduling.
ProLine
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
Why Dolphin Sigma is our pick
Dolphin Sigma
Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
$2,399
Buy Dolphin SigmaDolphin Oasis Z5i or Dolphin Sigma: our take
Dolphin Oasis Z5i and Dolphin Sigma 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
Both robots are 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. Dolphin Oasis Z5i lists CleverClean navigation. Dolphin Sigma lists 2 active brushes, SmartNav 3.0 with gyroscope navigation, and Triple commercial-grade DC motors.
Filtration and debris
Dolphin Oasis Z5i includes Basket and UltraFilter; Dolphin Sigma includes Standard filter and NanoFilters. Both have documented fine-debris media, so basket capacity and ease of cleaning matter more than fine-particle capability. Dolphin Oasis Z5i also has the better documented path for bulky leaves and larger debris.
Controls and day-to-day ownership
Dolphin Oasis Z5i provides a weekly timer and smartphone control; Dolphin Sigma provides a weekly timer, smartphone control, and included remote control. Dolphin Oasis Z5i uses continuous corded power, while Dolphin Sigma uses a 55 ft corded cable with an anti-tangle swivel. Dolphin Oasis Z5i is listed at 26.7 lb versus 24.6 lb for Dolphin Sigma; that 2.099999999999998 lb difference matters when lifting the robot from the pool.
Price, warranty and the decision
Each lists a 3-year manufacturer warranty. Pool Express pick: Dolphin Sigma. Dolphin Sigma adds gyroscope-assisted navigation. Dolphin Sigma weighs 24.6 lb versus 26.7 lb. Choose Dolphin Oasis Z5i when it is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning with app scheduling.
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 Oasis Z5i | Dolphin Sigma |
|---|---|---|
| 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 | Yes |
| Smartphone app | Yes | Yes |
| Anti-tangle swivel | Yes | Yes |
| 3-year warranty | Yes | Yes |
| 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 Oasis Z5i stands out
Dolphin Oasis Z5i is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning with app scheduling.
- Includes a large-debris bin or bag for leaves
- 2.5-hour cycle, pools up to 50 ft
Where Dolphin Sigma stands out
Dolphin Sigma is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.
- Adds gyroscope-assisted navigation
- Weighs 24.6 lb versus 26.7 lb
Dolphin Oasis Z5i vs Dolphin Sigma 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 Oasis Z5i | Dolphin Sigma |
|---|---|---|
| Best fit | Inground pools up to 50 ft that need floor, wall and waterline cleaning with app scheduling. | Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris. |
| Starting price | See product | $2,399 |
| Pool type | Inground | Inground |
| Maximum pool length | Up to 50 ft | Up to 50 ft |
| Cleaning coverage | Floor, Walls, Waterline | Floor, Walls, Waterline |
| Power | Corded | Corded |
| Filtration | Basket, UltraFilter | Standard filter, NanoFilters |
| Scheduling | Weekly schedule + app | Weekly schedule + app |
| App and remote | App control | App + included remote |
| Cable | Not listed | 55 ft with anti-tangle swivel |
| Robot weight | 26.7 lb | 24.6 lb |
| Warranty | 3 years | 3 years |
Choose Dolphin Sigma
Dolphin Sigma is the Pool Express pick in this matchup. Dolphin Sigma adds gyroscope-assisted navigation. Dolphin Sigma weighs 24.6 lb versus 26.7 lb.
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