Choosing a Robot by Pool Type

The four pool types

Above-ground pools

An above-ground pool is a flat floor at a uniform shallow depth with soft or thin metal walls. A wall-climbing robot has nothing useful to do there, and on a soft-sided pool the climbing action works against the structure.

Buy a machine built for this geometry. Dolphin's Nautilus AG is one; several cordless brands publish above-ground-specific models. They are simpler and cheaper because the job is simpler, not because they are inferior versions of something else.

Vinyl liners

A vinyl liner is a printed surface. Aggressive brushing wears the print off in the areas the robot favors, which shows up as pale patches long before the liner itself fails.

Look for soft or rubber brushes rather than aggressive PVA, and check that the maker states vinyl compatibility. The same caution applies to your manual brush - stainless bristles will cut a liner outright.

Fiberglass

Fiberglass is the smoothest common pool surface, which means two things: it needs the least aggressive brushing, and traction becomes the limiting factor. A robot that climbs a rough plaster wall easily can slip on fiberglass.

Where a maker states fiberglass compatibility explicitly, that is worth more than a general wall-climbing claim. Where nobody states it, it is a question worth asking before buying.

Gunite, concrete and plaster

The most forgiving surface for a robot and the most demanding job. Rough plaster shelters biofilm and algae in a way smooth surfaces do not, which is exactly why black algae is a plaster problem rather than a vinyl one.

Here the most aggressive brushing available is a benefit rather than a risk, and motor power matters because the surface resists.

Shape and features change the answer too

• **Steps and benches** are where cheaper robots get stuck or simply skip. If your pool has a large tanning ledge, look for a machine that states step or shallow-area cleaning specifically - Aiper states shallow-area cleaning on the Scuba S1, for example.
• **Freeform shapes** favor a robot that maps rather than one running a fixed pattern, because a fixed zig-zag in an irregular pool leaves the same areas uncleaned every cycle.
• **Deep ends over 8 ft** are worth checking against the cable length on a corded unit, and against the coverage figure on a cordless one.
• **Long pools over 50 ft** need a published length or coverage rating that covers them. Polaris publishes 60 ft with a 70 ft cable on the 9550 Sport; most makers publish nothing.

The picks

Top pick - Above-ground pools

Dolphin Nautilus AG Robotic Pool Vacuum, above ground

Built for above-ground pools specifically, which matters because a wall-climbing robot on a soft-sided pool is the wrong tool.

The published figure

Purpose-built for above-ground pools, active scrubber brush, top-load filter

Above-ground pools have flat floors, shallow uniform depth and walls that a climbing robot has no business climbing. A unit designed for them is simpler and cheaper for good reasons.

Buying an in-ground robot for an above-ground pool means paying for climbing you cannot use and, on a soft-sided pool, do not want.

Top-load filter access is the same convenience as the rest of the Dolphin line.

What it does well

• Designed around the actual geometry of an above-ground pool
• Cheaper than the in-ground units for the same brand quality
• No battery to degrade

What it costs you

• Will not climb walls, by design
• Corded

Skip it if you own an in-ground pool — you would be giving up the wall and waterline cleaning.

Check price on Amazon

#ad · how this is funded

Pick 2 - Small pools

Wybot B1 Cordless Robotic Pool Cleaner

Explicitly rated for pools up to 1,150 sq ft, which is a more useful number than a runtime figure with no area attached.

The published figure

Rated by the maker for pools up to 1,150 sq ft, 120 min runtime, 180 micron filter

Wybot publishes a coverage area for this unit rather than leaving you to infer it. 1,150 sq ft is roughly a 16 x 32 pool including the walls.

Buying a unit rated well above your pool wastes money; buying one rated below it means the cycle ends before the pool is done. The published area is how you avoid both.

180 micron single-stage filtration here, not the dual stage of the C2. That is the trade at this size and price.

What it does well

• Coverage area published, so sizing is a decision rather than a guess
• Compact and light to lift out
• Quad roller brushes for edge work

What it costs you

• Single-stage 180 micron filter passes fine silt
• 120 minutes is short for anything above its rated area

Skip it if your pool is larger than about 1,150 sq ft. The maker's own rating is telling you not to.

Check price on Amazon

#ad · how this is funded

Pick 3 - In-ground pools up to 50 ft

Dolphin Nautilus CC Plus Wi-Fi Robotic Pool Vacuum

The corded default. Mains power means runtime is not a specification you have to think about.

The published figure

Corded, wall-climbing with waterline scrubbing, ultra-fine top-load filter cartridges

A corded robot has no battery to degrade and no runtime ceiling. That single fact removes the constraint every cordless unit on this page is designed around.

Wall climbing and waterline scrubbing are the two features that separate a robot from a floor vacuum, because the waterline is where the oily scum line forms and no floor-only unit touches it.

The cable is the cost: it tangles, and you have to lift a wet robot with a cord attached out of the pool.

What it does well

• No runtime limit and no battery to degrade
• Climbs walls and scrubs the waterline, not just the floor
• Top-load filter cartridges, which are the easiest kind to empty

What it costs you

• Cable tangling on pools with a lot of steps and features
• Heavier to lift out than a cordless unit

Skip it if your pool has no convenient power outlet, or you want to drop a cleaner in and walk away without managing a cord.

Check price on Amazon

#ad · how this is funded

Pick 4 - Finest published filtration

Wybot C2 Cordless Pool Vacuum for In-ground Pools

A 10 micron secondary filter is the finest figure published by any robot here, and it is the one that decides whether the water looks clean afterwards.

The published figure

180 min runtime, up to 2,152 sq ft per cycle, 10 micron ultra-fine plus 180 micron primary filter

Wybot's own product page states a 10 micron ultra-fine filter behind a 180 micron primary. Most robots publish one number or none at all.

That matters because 180 micron catches leaves and grit while fine silt, pollen and dead algae pass straight through and go back into the water. The second stage is what stops that.

Wybot also publishes coverage per cycle — 2,152 sq ft — which is the honest way to compare against your own pool rather than against a runtime number in isolation.

What it does well

• 10 micron secondary filtration, the finest published figure in this roundup
• Coverage published per cycle, not just runtime
• Three brushless motors driving suction

What it costs you

• Fine filtration means more frequent filter cleaning
• 180 minutes is shorter than the longest-running units here

Skip it if your pool only ever collects leaves. You would be paying for filtration you never use.

Check price on Amazon

#ad · how this is funded