Pool Robot Filtration Explained: 150 vs 180 vs 3 Micron Filters (Do You Need Ultra-Fine?)
Our top picks
180 µm mesh plus a replaceable 3 µm ultra-fine insert, about $700Aiper Scuba S3Cordless · Up to 4 hr · Floor + Walls + Waterline8.5Price tier: Mid-range, $500–$1,000Check price on Amazon
180 µm plus 3 µm ultra-fine filter, 2-year warranty, just under $500Aiper Scuba S1 (2026)Cordless · Up to 3 hr · Floor + Walls + Waterline8.3Price tier: Budget, under $500Check price
Open a pool robot’s spec sheet and you’ll find a micron rating: 200 µm on the Betta SE Plus, 180 on the Aiper Scuba S1 and S3, 150 on the Beatbot Sora models and Aiper EcoSurfer S2, and a “3-micron” option on several. It sounds like a simple more-is-better scale. It isn’t.
What a micron is
A micron is a millionth of a meter. For scale, a human hair is roughly 50–100 microns wide. Filter ratings describe the particle size a filter can trap: a 150-micron filter lets through particles smaller than that, a 3-micron filter catches almost everything visible and a lot that isn’t.
The three tiers
| Rating | Typical on | What it catches |
|---|---|---|
| 200 µm | Betta SE Plus basket | Leaves, bugs, pollen clumps, pet hair |
| 150–180 µm | Most baskets: Beatbot Sora, Aiper EcoSurfer S2, Scuba S1/S3 mesh, Wybot C2 Vision | Leaves, sand and coarse dust |
| 3 µm | Aiper Scuba S1/S3 insert; optional on Beatbot Sora | Fine dust, silt, pollen and fine sediment that cloud water |
Where each tier wins
Coarse and large baskets (150–200 µm) keep running with leaf loads. The Sora 30 has a 5 L basket; the Betta SE Plus has an extra-large basket on the surface. For leaf-heavy pools, capacity matters more than micron.
Ultra-fine (3 µm) matters if the water gets cloudy from fine particles that pass through a standard basket. The Scuba S3 and S1 ship with the option; the Sora 10 and Sora 30 offer it as an accessory.
The catch: clogging and maintenance
Finer filters fill faster, so the robot may slow or stop sooner, and you’ll rinse more often. A first-of-season clean in a dirty pool can overwhelm any filter. Remove the ultra-fine insert for heavy debris and put it back for polishing. See maintenance and troubleshooting for what to do when suction drops.
Does fine filtration replace your pump filter?
No. Your pool’s circulation filter does the real water polishing; a robot’s filter reduces how much fine debris is stirred up and re-circulated. It helps clarity, but it isn’t a substitute for your main filter or water chemistry.
How to choose
- Leafy pool: a big basket and a skimmer. See skimmer vs vacuum robot.
- Dusty, sandy or pollen-heavy pool: a robot with a 3 µm option (Scuba S1 or S3).
- Both: run the coarse basket first, then switch to the fine filter.
For the full set of picks, see the best robotic pool cleaners of 2026.