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Head-to-head · Best Under-Sink Water Filters

Aquasana Claryum AQ-5300+ vs Cloud RO Under-Sink Reverse Osmosis System

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

Cloud RO Under-Sink Reverse Osmosis System comes out ahead by a clear margin (4.4 vs 3.9). Cloud RO Under-Sink Reverse Osmosis System is best for: households that want app-monitored reverse osmosis water without an under-sink outlet. Read the strengths below before deciding.

Aquasana Claryum AQ-5300+
Ranked #4 in Best Under-Sink Water Filters
Aquasana Claryum AQ-5300+
1 sourceall derived$199.99as of Sep 28

The Aquasana Claryum AQ-5300+ is the best all-around under-sink carbon filter, pairing NSF/ANSI 42, 53 and 401 certification with a fast-flow three-stage design that keeps healthy minerals in the water. It reduces 99% of 77 contaminants, including lead, chlorine, PFAS and pharmaceuticals, without the water waste of reverse osmosis. The trade-off is a 6-month filter life and a higher per-gallon cost. For clean, great-tasting water, it's a leading pick.

Strengths
  • — Triple-stage Claryum filtration reduces 99% of 77 contaminants including lead, chlorine, PFAS and pharmaceuticals
  • — NSF/ANSI 42, 53 and 401 certified, covering taste, health contaminants and emerging compounds
  • — Retains beneficial minerals like calcium and magnesium rather than stripping them
Watch-outs
  • — Filters last about 6 months or 800 gallons, shorter than some rivals
  • — Requires a spare faucet hole or drilling for the dedicated faucet
  • — Does not reduce total dissolved solids the way reverse osmosis does
$199.99 · Check Price on AmazonFull review →
Cloud RO Under-Sink Reverse Osmosis System
Higher ratedRanked #2 in Best Under-Sink Water Filters
Cloud RO Under-Sink Reverse Osmosis System
2 sourcesall derived

The Cloud RO is a battery-powered, app-connected under-sink reverse osmosis system with eight filtration stages, remineralisation, a 2.8-gallon tank and a rated 80 gallons per day. The Spruce named it its best smart system after a year of use, citing easy setup, useful app monitoring and alerts, and enough output for a large household; Good Housekeeping found it compact, quiet and noticeably better tasting than NYC tap water. Both flag the cost: Good Housekeeping puts the starting price at about $600 with $200 replacement filters, and The Spruce notes a 1:1 waste ratio. It suits households that want RO water with real-time monitoring; buyers on a budget or short of cabinet space should look elsewhere.

Strengths
  • — The Spruce found setup easy, with well-labelled lines and fittings
  • — App shows tap and filtered water quality and sends filter-change alerts
  • — Battery powered, so no outlet is needed under the sink
Watch-outs
  • — Costs more than many RO systems, and replacement filters cost about $200
  • — 1:1 waste ratio, more wasteful than The Spruce's top iSpring pick
  • — Included faucet feels a little flimsy, and flow sputters on first use each day
Buy at cloudwaterfilters.comFull review →

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

How they stack up

Aquasana Claryum AQ-5300+

Unlike the Clearly Filtered 3-Stage, the AQ-5300+ carries multiple NSF certifications rather than relying on third-party testing alone.

Cloud RO Under-Sink Reverse Osmosis System

Unlike the Waterdrop G3P800 Tankless Reverse Osmosis System, the Cloud RO stores water in a 2.8-gallon tank and runs on a battery rather than mains power. Like the APEC Water ROES-PH75 Essence Alkaline system it adds minerals back after RO filtration, but it is priced from about $600 and adds app monitoring; the Aquasana Claryum AQ-5300+ is a non-RO filter for buyers who want to avoid a tank altogether.

Specs side-by-side

SpecAquasana Claryum AQ-5300+Cloud RO Under-Sink Reverse Osmosis System
Filtration3-stage Claryum—
CertificationsNSF/ANSI 42, 53, 401—
Contaminants Reduced99% of 77 (lead, chlorine, PFAS, pharmaceuticals)—
Filter Life6 months / 800 gallons—
Mineral RetentionYes (calcium, magnesium)—
FaucetDedicated brushed nickel included—
Install Time~30-45 min DIY—
FlowMax Flow (no tank)—
Dimensions12"L x 4.25"W x 12.88"H11 x 7 x 16 inches
MaterialMetal—
Type—Under-sink reverse osmosis with tank
Daily Production Rate—80 gpd
Filtration Stages—8
Tank Capacity—2.8 gallons
Power—Battery
Waste Ratio—1:1
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