Robotic pool cleaner comparison

Clear S vs Dolphin M400

A side-by-side comparison of pool fit, cleaning coverage, filtration, controls and the better Pool Express option.

By Brian Williamson, Pool Express product specialist
Updated November 9, 2026

Pool Express pick

Our pick: Clear S

Clear S is the Pool Express pick in this matchup. Clear S includes a 59 ft cable with anti-tangle swivel. Clear S's documented advantages include ultraFilter fine filtration.

Buy Clear S Compare every robot

Pool Express pick

CLEAR

Clear S

Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.

Current price $1,749MSRP ~~$2,749~~ Save $1,000

Buy Clear S

M-Line

Dolphin M400

Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.

Listed price $1,599

View better alternatives

Pool Express pick

Why Clear S is our pick

Pool Express pick

Clear S

Inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.

$1,749

Buy Clear S

Buying guidance

Clear S or Dolphin M400: our take

Clear S and Dolphin M400 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. Clear S's documented cleaning system includes 2 active brushes, Intelligent navigation (C9 microprocessor), and Quad (2 pump + 2 drive) motors.

Filtration and debris

Clear S includes UltraFilter; Dolphin M400 includes Standard filter and UltraFilter. Both have documented fine-debris media, so basket capacity and ease of cleaning matter more than fine-particle capability.

Controls and day-to-day ownership

Clear S provides a weekly timer, smartphone control, and included remote control; Dolphin M400 provides smartphone control. Clear S uses a 59 ft corded cable with an anti-tangle swivel, while Dolphin M400 uses a 60 ft corded cable with an anti-tangle swivel.

Price, warranty and the decision

Clear S is listed at $1,749 and Dolphin M400 at $1,599; Dolphin M400 is $150 less. Each lists a 3-year manufacturer warranty. Pool Express pick: Clear S. Clear S includes a 59 ft cable with anti-tangle swivel. Clear S's documented advantages include ultraFilter fine filtration. Choose Dolphin M400 when it is the better fit for shoppers prioritizing the lower $1,599 starting price.

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	Clear S	Dolphin M400
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	No	No
Automatic scheduling	Yes	Not listed
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 Clear S stands out

Clear S is the better fit for inground pools up to 50 ft that need floor, wall and waterline cleaning, with fine debris.

59 ft cable with anti-tangle swivel
UltraFilter fine filtration

Where Dolphin M400 stands out

Dolphin M400 is the better fit for shoppers prioritizing the lower $1,599 starting price.

Is listed $150 lower
60 ft cable with anti-tangle swivel