Does a robot pool cleaner replace the pool’s pump and filter?
Some robot pool cleaners list filters as fine as the cartridge on a pool's equipment pad, and that pad's pump can be one of a home's biggest power draws.
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Near the top of its product page, the Wybot C2 Vision advertises “180μm large-particle cartridges with 10μm ultra-fine filters”. Ten microns sits inside the range Hayward gives for cartridge filters, the kind that sit beside the pump on a pool’s equipment pad.
That pad costs money every hour it runs. A pool pump “could be your home’s second largest energy user,” in ENERGY STAR’s words, at as much as $310 a year. So if a robot filters down to 10 microns while it cleans, could your pump run less? Could the filter go?
Wybot takes up the question itself, further down. Its FAQ asks, “Can the robot manage water quality or perform ultra-fine filtration?” and answers:
No. The robot is designed for debris cleaning, not water quality management or ultra-fine filtration. For healthy and clear water, it should be used together with your pool’s circulation and filtration system, as well as proper chemical treatment.
So one page sells “ultra-fine filters” and also says the robot does no ultra-fine filtration. Both statements hold up once three things are pulled apart: how fine a robot’s filter is, how long it runs, and which water it ever touches.
How fine the robots filter
A pool’s own filter comes in one of three kinds, and Hayward makes all three. Sand catches particles down to 20 to 40 microns, a cartridge 10 to 20, and diatomaceous earth (DE) 3 to 5. The makers of the C2 Vision, the Beatbot AquaSense 2 and the Maytronics Dolphin Nautilus EON 100 list their robots’ filters and suction this way:
Maker spec pages
Filter ratings and suction as three makers list them
| Robot | Filter rating listed | Suction listed |
|---|---|---|
| Wybot C2 Vision | 180-micron cartridges plus 10-micron fine filters | 3,883 gallons an hour in the overview, 3,592 in the page comparison table |
| Beatbot AquaSense 2 | 150 microns | 5,500 gallons an hour |
| Maytronics Dolphin Nautilus EON 100 | 60 microns in one line, 70 in another | Not listed |
Set beside those ranges, the Beatbot’s 150-micron filter is nearly four times the coarse end of a sand filter. The EON 100’s filter is rated at 60 microns in one line and 70 in another, and either figure is coarser than sand.
Only the Wybot’s fine stage lands in cartridge territory. And the suction ratings, thousands of gallons an hour, describe water the robot draws in near the surface it is scrubbing.
The circuit that leaves the pool
Two circuits
One of them leaves the pool
- SkimmerThe pool's own circuit leaves the shell here, through the wall at the surface.
- Pump and filterStanding on the deck, outside the water. Skimmer, pump, filter, return: the whole volume passes here continuously, which is what lets this circuit also carry heat and chemistry past a sanitiser.
- Robot basketIntake underneath, basket inside, outlet on top. The cleaner's circuit closes inside the water and never crosses the wall: it takes debris out of the water it drives through, and does not turn the pool over.
A robot pulls water in through an intake on its underside, passes it through the filter in its housing and pushes it back out, usually through a vent on top. That water never leaves the pool.
The pool’s own circuit runs outside it. The pump draws water through the skimmers and main drain and forces it through the filter on the equipment pad, and through a heater and a chlorinator or salt cell where a pool has them. Return jets in the walls send it back.
The skimmers pull floating leaves, pollen and oils off the surface for as long as the pump runs, and the return jets spread whatever the chlorinator or salt cell has added across the whole body of water. A robot working the floor passes none of its water through that equipment.
A robot’s run is short, too. Maytronics offers the EON 100 in cycles of 1.5, 2 or 2.5 hours, Wybot quotes a 180-minute runtime in Eco mode, and Beatbot claims up to four hours of floor cleaning per charge.
Even four hours is shorter than a lean filtration schedule of six hours a day, one that uses 75 percent less energy than running the pump around the clock.
Sanitizer moves with the pump
Chlorine works only where it reaches. It might come from a salt cell, a feeder in the plumbing or a jug you pour in at the deep end. Either way, the flow from the return jets carries it through the pool, and the filter keeps removing the fine organic matter that would otherwise use it up.
Richard Wang, chief executive of the robot maker Aiper, drew the same line in an interview: robotic cleaners “are designed primarily for physical cleaning. Water chemistry management and filtration system upkeep still need to be handled through other equipment or routine maintenance.”
Maytronics claims more for its robots. Their “advanced multi-layer filtration” captures “microscopic particles like pollen, dust, and bacteria,” the company says, and “This deep filtration reduces the need for excessive chemical treatments.”
No figure comes with that claim. And the EON 100’s own filter, at 60 or 70 microns, is more than ten times coarser than the 3 to 5 microns of a DE filter.
When a pool has gone cloudy, the robot makers themselves put the equipment pad first. Wybot’s FAQ warns that water that “is extremely dirty or contains a large amount of suspended particles” may affect the robot’s cleaning efficiency, and recommends “running your circulation and filtration system first to improve water clarity before using the robot.”
Where a robot changes the pump’s day
A robot can lower your pump bill in one situation, and it depends on what cleaned the pool before it. Suction-side cleaners run off the pool’s own pump, and many pressure-side cleaners need it or a separate booster pump.
ENERGY STAR notes that “Filtration, for example, only requires half the flow rate of running a pool cleaner,” and that single-speed pumps are set to the higher speed the cleaner needs, wasting energy during filtration by running faster than necessary.
Term
Suction-side and pressure-side cleanersAutomatic pool cleaners with no motor of their own, moved by water in the pool’s plumbing. A suction-side cleaner hooks up to a skimmer and is driven by the suction the pump draws through it. A pressure-side cleaner is driven by water pushed back into the pool, from the pool’s pump or a separate booster pump.A robot carries its own motor and filter. As the writer who interviewed Wang put it, “there’s no extra strain on your pump.” So if you swap a pump-driven cleaner for a robot and your pump is variable-speed, the filtration schedule can run at the lower speed.
Halving a pump’s speed cuts its energy use to one-eighth. The hours stay on the timer, though. Skimming the surface, spreading the chlorine and filtering the whole pool all happen in the pump’s circuit, and a robot’s water never joins it. What a robot can change on your equipment pad is how fast the pump runs those hours.
