Choosing between the Dolphin M400 vs Dolphin S400 means evaluating two elite robotic pool cleaners designed for serious in-ground pool maintenance. Both models are engineered by Maytronics for pools up to 50 feet in length, offering a premium blend of scrubbing power, filtration technology, and smart automation. While they share core capabilities, there are key differences in filtration design, smart navigation, and advanced control features that set them apart.
This comprehensive comparison explores every critical factor, helping pool owners make a confident, informed decision.
Contents
Differences Between Dolphin M400 vs Dolphin S400
Design Comparison
The Dolphin M400 is built like a tank, weighing approximately 25 pounds and engineered with a rugged exterior ideal for intensive pool maintenance. Its PowerStream mobility system uses multi-directional jets to ensure maximum grip on walls and angled surfaces, making it ideal for deep pools or those with unique shapes. The multi-layer filter basket is top-loading and easily accessible, separating fine and coarse debris efficiently within the same unit.
The Dolphin S400 is noticeably lighter at 18.5 pounds, making it easier to remove from the pool after each cleaning cycle. It features a sleek, compact chassis and includes interchangeable fine and ultra-fine filters, giving users the option to tailor filtration depending on seasonal debris conditions. The S400 is ergonomically designed for residential use, combining performance with convenience.
Winner: Dolphin S400
With a lighter build and flexible filtration design, the S400 is better suited for everyday handling and variable pool conditions.
Cleaning Performance Comparison
The Dolphin M400 excels with its dual active brushes, spinning faster than the tracks to effectively agitate dirt, algae, and fine biofilm from the floor, walls, and waterline. Backed by PowerStream propulsion, it maintains strong vertical grip and navigation across complex surfaces. With a suction rate of 4,500 GPH, it delivers consistent debris collection throughout a 2 to 2.5-hour cycle. The multi-layer filtration system separates larger leaves and debris from finer particles, minimizing clogging and allowing uninterrupted cleaning.
The Dolphin S400 matches the M400 with dual active brushes and also cleans the waterline effectively. However, it doesn’t include PowerStream, relying instead on powerful motor steering and smart sensors to navigate walls. It offers a 1.5-hour quick clean cycle and a standard 2-hour cycle, providing flexibility based on your cleaning needs. The interchangeable filters allow fine control over debris management, but they may require more frequent cleaning in heavy-leaf seasons compared to M400’s layered system.
Winner: Dolphin M400
Thanks to its PowerStream propulsion and more integrated filtration system, the M400 provides a deeper, more continuous clean with fewer interruptions.
Feature Comparison
The Dolphin M400 offers Wi-Fi connectivity through the MyDolphin™ Plus App, allowing remote scheduling, mode switching, and performance tracking. Its PowerStream mobility system enhances directional precision and responsiveness, especially on vertical and uneven pool walls.
The Dolphin S400 also integrates with the MyDolphin™ Plus App and includes a weekly scheduler, providing the same wireless convenience. Though it lacks PowerStream propulsion, it performs well using its intelligent navigation algorithms. It delivers consistent performance in standard pool layouts and offers similar app-level functionality for on-the-go control.
Winner: Dolphin M400
Although both models offer smart features, the M400’s added mobility tech gives it the edge in adaptability and real-time responsiveness.
Quick Rundown Of Dolphin M400
Quick Rundown Of Dolphin S400
Conclusion
Choose the Dolphin M400 if you want a high-powered robotic cleaner with superior wall performance, integrated filtration, and advanced navigation. Its PowerStream system and multi-layer basket make it the top choice for challenging pools or those that regularly accumulate heavy debris.
Choose the Dolphin S400 if you prefer a lighter, more agile cleaner with filter flexibility and quick-clean cycle options. It’s perfect for residential pool owners who value convenience and seasonal adaptability.
Overall Winner: Dolphin M400
With stronger wall-gripping performance, smarter propulsion, and layered filtration, the Dolphin M400 outperforms in long-term cleaning efficiency and durability, making it the better investment for premium pool care.