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Internet #206816589

Model #THD-RO3-R

Stage 1 and 3 RO Filter Replacement

  • Compatible with Aquasana AQ-RO3.56 drinking water system
  • Filters out chlorine, lead, mercury, arsenic, and more
  • Carbon and claryum filters last for up to 6 months or 365 gal.
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How to Get It

Product Overview

The THD-RO3-R consists of Carbon (Stage 1) and Claryum (Stage 3) filter cartridge replacements for the THD-RO-3 OptimH2O Reverse Osmosis Drinking Water System. Aquasana OptimH2O delivers the best drinking water available for optimal hydration. It is the first system of its kind to pair powerful reverse osmosis filtration with Claryum selective filtration PLUS re-mineralization. Removes the most contaminants from your water while maintaining the benefits of healthy minerals that other reverse osmosis systems simply remove. Reverse Osmosis is the only proven water filtration method on the market to effectively remove fluoride from regular tap water. Aquasana's filter removes over 95% of fluoride for optimally healthy, clean water. The OptimH2O also re-mineralizes water to put back the healthy minerals lost in the reverse osmosis process like calcium, magnesium, and potassium for optimally alkaline, pH balanced water.
  • Replacement cartridge for AQ-RO3.56
  • Carbon and claryum filters (stage 1 and 3) should be replaced every 6 months or 365 Gal. for optimal filter effectiveness
  • Other reverse osmosis systems typically reduce 5-15 contaminants, Aquasana reduces 74
  • Reverse osmosis reduces 14 impurities including fluoride, nitrates, nitrites, lead, radium and arsenic
  • Selective claryum filtration reduces 60 contaminants including chlorine, chloramines, heavy metals, pesticides, and herbicides
  • Re-mineralization designed to provide healthy amounts of calcium, magnesium and potassium for optimally alkaline, pH balanced water
  • Full system NSF certification, not just select components like tubing or tanks, Aquasana proudly displays the NSF logo for standards 42, 53, and 58
  • Unlike other water filter certifications, full NSF certification requires extraction testing to ensure the system does not leach contaminants back into your water
  • Removes up to 99% of contaminants including arsenic, chlorine, lead, fluoride, heavy metals, chloramines, mercury, asbestos, and more
  • 1 year manufacturer's warranty and toll-free lifetime support backed up by Aquasana water filtration specialists based in Texas (866) 662-6885
  • Replacements engineered for ease; eco-friendly carbon and claryum filter housings easily twist off so replacing your filters is a snap

Additional Resources

From the Manufacturer

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BrandGEAquasanaBrondellGE Profile
NameReverse Osmosis Replacement Filter SetStage 1 and 3 RO Filter ReplacementCapella Reverse Osmosis Sediment Carbon Water Filter CartridgesProfile Reverse Osmosis Replacement Membrane
Buy 4 or more $57.58
Water Filtration System TypeReverse OsmosisReverse OsmosisReverse OsmosisReverse Osmosis
Replacement Filter TypeReverse Osmosis Replacement FiltersReverse Osmosis Replacement FiltersReverse Osmosis Replacement FiltersReverse Osmosis Replacement Filters
Number of filters included2221
Product Height (in.)10.75 in9.50 in11.5 in8.5
Filtration MethodCarbon BlockCarbon BlockCarbon Block,SedimentCarbon Block
Product Depth (in.)2.55 in2.125 in2.25 in1.75
Pack Size2221
View ProductView ProductView ProductView Product



Product Depth (in.)2.125 inProduct Height (in.)9.50 in
Product Width (in.)2.125 in


Brand/Model CompatibilityAQ-RO3.56FeaturesTwist and lock design
Filtration MethodCarbon BlockNumber of filters included2
Pack Size2Product Weight (lb.)1.3 lb
Replacement Filter TypeReverse Osmosis Replacement FiltersReturnable90-Day
Water Filtration System TypeReverse Osmosis

Warranty / Certifications

Manufacturer Warranty90 day manufacturer warranty

Questions & Answers

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Customer Reviews

  • 4.7
    out of 102 reviews
  • 94%recommend this product
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Showing 1-10 of 102 reviews
I would definitely recommend this product, We Love It!
I love this reverse osmosis system, wish I could buy it for all my family ! It taste great, make our coffee taste great ! We could not believe the filter when we change it after 6 months! It give us pease of mind, that we are doing something so healthy that is is a no brainer!
  • Verified Purchase
  • Recommended
  • Verified Purchase
  • Verified Purchase
Excellent inexpensive product
This filter system is easy to maintain, never leaks and is relatively inexpensive
  • Verified Purchase
  • Recommended
Simple design
I love my water filter. The water tastes great and my pets like it too. I can also use the water in my steam mop and humidifier without leaving a residue.
  • Verified Purchase
  • Recommended
It was easy to install, and the system works well. You will be happy with the system.
  • Verified Purchase
  • Recommended
Great product from a great company
Being a long time customer of Aquasana, starting with a countetop filter years ago and eventually upgrading to an undersink unit, there was no question about choosing the OptimH2O reverse osmosis unit for our new home. Installation went without a hitch and I even learned a bit about working with PEX in the process. Customer service has always been top notch and warranty replacement was above and beyond with a previous filter unit.
  • Verified Purchase
  • Recommended
Replacing the filters too difficult
I like the result but replacing cartridges extremely difficult for arthritic old lady. And now there is a leak and the plumbers I have called say they have no experience fixing this product. So while the result is good, maintenance of the system seems problematic except for an experienced (and strong) do-it-yourselfer. Additionally, the Aquasana help line provides little or no assistance or guidance.
  • Verified Purchase
Great improvement in taste of water
I have a love/hate relationship with my Aquasana reverse osmosis. Being in the grey hair catagory of life we hired a plumber to install the product. Even he had a problem and installed one of connectors incorrectly. Water all over the counter top. My husband rigged a diversion into the sink until he felt up to getting under the sink and figuring out what had happened. Plumber had installed the connector backwards. My husband fixed it and it's been working just as it should for two years. Replacing the filters under the sink every six months is for the young and agile - not us. So we hire a young neighbor to come over and do the chore for us. Installation and changing the filters definitely not for oldsters whose bones creak. Thank goodness for kind neighbors.
  • Verified Purchase
  • Recommended
Good Product and Good Value
We have had it for over 2 years. Also have the shower filtration system. Very good.
  • Verified Purchase
  • Recommended
Showing 1-10 of 102 reviews