Pick a Pool Cleaner by the Debris You're Fighting

Almost every pool cleaner guide is organized by brand or by price. Both are the wrong axis, because they tell you nothing about whether a machine will solve the problem in front of you. A $2,300 flagship with 3-micron filtration is genuinely worse at oak leaves than a $499 machine with a 5-liter basket — and that is not a close call.

The four specifications, and which debris each one governs

Basket volume — for leaves, needles and anything bulky

A robot’s cycle is limited by debris capacity, not runtime. Once the basket is full, flow collapses and the rest of the cycle collects essentially nothing: the machine drives around with a plug of wet debris in it. That is why “it is not strong enough” is the standard autumn complaint, and it is a capacity problem rather than a suction one.

Published figures are the thing to compare. Beatbot publishes 5 liters on the Sora 10 and 30 and 9 liters on the iSkim skimmer; most machines in the $300-600 band carry 1-2 liters and publish nothing at all, which is itself informative. The leaf roundup ranks on this.

Micron rating — for sand, silt, pollen and dead algae

A micron is a thousandth of a millimeter. Pool sand runs roughly 100-500 microns; silt, pollen and post-shock dead algae are 2-50. A 180-micron basket — what most machines ship with — passes the entire fine fraction straight back into the water. All it has done is relocate your problem, which is exactly what “it just pushes the sand around” means.

Aiper publishes 3 micron on the Obsidian and X1 Pro Max; WYBOT publishes a 10-micron layer on the C2; a Dolphin with $26 ultra-fine cartridges does the job for the least money in the category. The filtration explainer sets out what each rating catches.

And here is the part most reviews get backwards: finer is not better. A 3-micron filter blinds within minutes in leaf litter, leaving you with worse suction than a coarse basket would have given you — and it stops the robot climbing walls too, since climbing depends on flow. Matched beats fine.

Surface interception — for pine needles and continuous tree fall

Debris floats for a few hours before it waterlogs and sinks. In that window it is weightless, has stained nothing, and has not touched your filter. After it sinks it becomes a vacuuming job, a tannin stain on your plaster, and a load on your filtration.

For a pool under a mature oak or pine, intercepting at the surface removes more total debris than any improvement to floor cleaning. That means a dedicated solar skimmer alongside a floor robot, or one of the three machines that does both.

A scrubbing pass along the line — for the waterline ring

The ring at your waterline is not dirt. It is body oil, sunscreen, hair product and airborne pollen bound into a greasy film, continuously replenished. Grease responds to repetition, not pressure.

Crucially, wall climbing is not waterline cleaning. A climb drags a brush vertically through the film once and generally smears it. A waterline pass travels along the line. Only a few machines publish the second — the waterline roundup separates them.

Most pools have mixed debris. What then?

Two sensible answers. The first is a staged filter: a coarse layer in front of a fine one, so leaf fragments do not blind the fine mesh. The WYBOT C2 and Beatbot’s dual-layer baskets both work this way, and it is the right architecture for a real pool.

The second is to swap filters seasonally — coarse through leaf and needle fall, fine for pollen season and after any shock treatment. Most machines accept more than one grade, and on a Dolphin a four-pack of ultra-fine cartridges costs about $26, which makes the swap trivial. Filters by brand has every price and fitment.

And one thing a robot will never do

Kill algae. Algae is a living biofilm anchored to your plaster or liner, and it is killed by chemistry. What a robot does is break the film open so the sanitizer can reach it, and then filter out the dead cells — which is genuinely useful and is not the same as removing algae. The algae page sets out the correct order of operations, and it starts with a test kit rather than a purchase.

If your debris is mixed or you are not sure which problem dominates, the selector tool works from your pool type, size, surface and dominant debris and narrows it to a shortlist. Or start with the master roundup, which covers the four gating specifications in order.

Every pick on this site is chosen from published specifications, retailer listings and owner reports by a rubric we publish in full. We do not physically test pool cleaners and nothing here implies that we do.