Head-to-Head Comparison
Dolphin T55i vs Dolphin Sigma
Our pool experts compare features, filtration, specs, and value to help you pick the right robotic pool cleaner.
Dolphin Sigma or Dolphin T55i — which wins?
Our pick: the Dolphin Sigma
Diving into the Dolphin T55i vs Dolphin Sigma, our pool experts weigh filtration, cleaning coverage, smart features, and value. For most pools, the Dolphin Sigma is the robot we recommend — and right now you save $500.
What Sets Them Apart
Key Differences
T55i
Sigma
- Includes NanoFilters™ - Captures small debris other cleaners miss
- Waterline Cleaning - Cleans the pool floor, wall, & waterline
- Triple Commercial Grade Motors - 3 ProLine Motors filter 4500 GPH+
- myDolphin Plus App - Schedule and clean the Sigma from anywhere
- Gyroscope - Gyroscopic sensors control and monitor every movement
- 3 Year Warranty - Longest warranty available
Side by Side
Feature Comparison
The features that matter most when comparing the Dolphin T55i and Dolphin Sigma.
| Feature | T55i | SigmaOur Pick |
|---|---|---|
| Standard Filter | ||
| NanoFilters™ | ||
| Wall Climbing | ||
| Waterline Cleaning | ||
| Programmable Weekly Timer | ||
| Gyroscope Navigation | ||
| Dual Stabilizer | ||
| Anti-Tangle Swivel | ||
| 3-Year Warranty |
Explained
Compare Features in Detail
NanoFilters™
Often overlooked, a NanoFilter™ can be the most important part of a pool robot. Without it, microscopic particulate — fine dust, pollen, and algae — passes right through the standard filters found on most robots. These ultra-fine filters trap that debris for a noticeably cleaner, healthier pool. Learn more ›
Programmable Weekly Timer
An automatic pool cleaner should be automatic. A programmable weekly timer sets the robot to clean on a schedule — every day, every other day, or a few times a week — without you turning it on and off.
Dual Stabilizer
Essential for waterline cleaning, dual stabilizers let the unit cling to the walls for a more precise, deeper clean at the waterline — with increased agility and an easy pickup handle.
Anti-Tangle Cable Swivel
Say goodbye to tangled cords. An anti-tangle swivel lets the robot move 360° around your pool without the cord getting tangled, so you can sit back while it cleans. Learn more ›
Warranty Coverage
A robot is only as good as its warranty. The Dolphin T55i is backed by a 2-year warranty, while the Dolphin Sigma carries a 3-year warranty. Buying through an Authorized Dealer like Poolbots gets you the full manufacturer warranty — never pro-rated or limited by cleaning cycles — plus a 30-day in-pool trial with no restocking fees. Learn more ›
Watch
Videos
See the Dolphin T55i and Dolphin Sigma in action.
The Details
Specifications
| T55i | Sigma | |
|---|---|---|
| Part Number | 99996245-WINI | 99991036-SPLI |
| Waterline Cleaning | Yes | Yes |
| Multi-Media® | No | No |
| Filters Included | 1 | 2 |
| Filter Cleaning | Top Access | Ultra-fine NanoFilters and Standard Filter Cartridge sets |
| Cleaning Coverage | Floor, Walls and Waterline | Floor, Walls, Waterline |
| Cleaning Cycle | 1.5, 2 hours | 2.5 hours |
| Number of Brushes | 2 | 4 |
| Cable Length | 60 ft | 60 ft |
| Anti-Tangle Swivel | Yes | Yes |
| Pool Types | In Ground | In Ground |
| Maximum Pool Size | 50 ft | 50 ft |
| Pool Shape | Rectangle, Oval, or Freeform | Rectangle, Oval, or Freeform |
| Obstacles | Steps, Ladder, Drain Cover, Ledges, Pop-Ups | Steps, Ladder, Drain Cover, Ledges, Pop-Ups |
| Surface | Gunite, Fiberglass, Vinyl, Liner | Concrete, Plaster, Gunite, Pebble, Tile, Vinyl Liner, Fiberglass |
| Media-Alert® | No | No |
| Automated Weekly Timer | Yes | Yes |
| Remote Operation | No | Yes - Through App |
| Restocking Fee | No | No |
| Warranty | 2 Years | 3 Years |
Go Deeper
Read Our Expert Reviews
Our in-depth reviews are written by pool experts to help you make an informed decision.
Dolphin T55i
Read Dolphin T55i ReviewDolphin Sigma
Read Dolphin Sigma ReviewKeep Comparing
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What’s Next?
Still narrowing it down? These expert guides and tools make it easy to find the right pool robot for your pool — most ship free, same day.
Pool Robot Buying Guide
Everything to know before you buy your first robot.
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Robot Selector
Answer a few quick questions and get a recommendation.
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Videos
Watch reviews, comparisons, and expert how-tos.
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Pool Volume Calculator
Calculate your exact pool volume to find the right robot.
Read more →Try It in Your Own Pool for 30 Days
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