SmartFlow® Reverse Osmosis Carbon Block and Advanced Carbon Block Replacements

4.3 out of 5 Customer Rating

SmartFlow® Reverse Osmosis Carbon Block and Advanced Carbon Block Replacements remove up to 99.99% of 90 contaminants, including lead, chlorine, microplastics, VOCs, and more.

  • In Stock
100368688 AQ-SFRO-S1S3
Water for Life® Price
$67.99 15% OFF + Free Shipping!

Benefits of Using a Reverse Osmosis Water Filter

Fast Water Flow

Water You Can Trust

Use only genuine Aquasana replacement filters for continued contaminant removal and system performance.

Delicious Taste

Peace of Mind

The SmartFlow® Reverse Osmosis system reduces 90 contaminants, including fluoride, arsenic, chlorine, lead, PFOA/PFOS, cysts, microplastics, and more.

Goodbye Fluoride

Value & Convenience

More clean, great-tasting water filtered at the most economical cost per gallon. Save money and time with fewer filter replacements.

Innovative Technology

Carbon & Claryum® Technology

Four different methods of advanced filtration work together in this system to reduce the maximum number of contaminants.

Easy Filter Replacements

Expertly engineered for easy replacement. Simply pop out and replace.


Minimal disposable plastic parts and no more single-use plastic bottles. Make a difference with this sustainable, eco-friendly solution.


This replacement comes with a 180-Day Limited Warranty and a 90-Day Satisfaction Guarantee so you can be confident in your purchase.


The SmartFlow® Reverse Osmosis system is WQA certified to NSF/ANSI Standards 42, 53, 58, 401, and CSA B483.1 for the claims specified on the Performance Data Sheet.

Pure Performance

The SmartFlow® Reverse Osmosis Carbon Block and Advanced Carbon Block Replacements replace Stages 1 and 3 in the SmartFlow® Reverse Osmosis (AQ-SFRO) and last for 6 months each.

Stage 1: Carbon Block

Reduces chlorine, taste and odor prior to reverse osmosis filtration.

Stage 3: Advanced Carbon Block

The SmartFlow® Reverse Osmosis is Aquasana's brand-new, high-efficiency reverse osmosis system. This system combines Aquasana's Claryum® filtration technology with reverse osmosis technology to remove up to 99.99% of 90 contaminants, including fluoride, arsenic, lead, chlorine, microplastics, PFOA/PFOS, and more.

The SmartFlow® Reverse Osmosis boasts one of the highest certified contaminant removal rates of all reverse osmosis Amazon's top-selling RO system is certified to reduce.*

Featuring our patented SmartFlow® technology, this system provides you with more pure water, less water waste, and longer filter life than the average RO filter. The system also restores healthy minerals that other reverse osmosis systems remove, providing you with optimum health and hydration.

*As of 7/7/2023.

Filter Life:
6 months
365 gallons
replacement filter

SmartFlow® Reverse Osmosis

High-efficiency reverse osmosis system removes up to 99.99% of 90 contaminants including fluoride, arsenic, chlorine, and lead.

Help & Support
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    How to Replace the SmartFlow® Reverse Osmosis Carbon Block Filters
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SmartFlow® Reverse Osmosis Carbon Block Filters Replacement
replacement filter

Need a replacement filter?

Water filters are an effective way to provide your household with healthy, great-tasting water. However, waiting too long to replace your filter can cause your system to stop working, and it may even become a source of bacteria or mold. Prevent filter contamination by replacing it on time.

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Get filters auto-delivered right when you need them — plus receive 15% off the price of replacement filters, free shipping, and an extended limited warranty on your filtration system. Protect your investment and save money with our no-contract Water for Life® program.

Ratings & Reviews
Customer Q&A
Aquasana FAQs
1. Do I need a plumber to install the system?
Our replacement filters are designed for easy replacements — no plumber required. Please read through the owner's manual carefully before attempting to replace your filters and/or review the product replacement video. If you have any questions or need assistance, our technical support representatives at 866-662-6885 can walk you through the installation process.

Stage 1 (Carbon Block) and Stage 3 (Advanced Carbon Block) filter cartridges should be replaced every 6 months or up to 365 gallons. Stage 2 (SmartFlow® Membrane) should be replaced every 12 months depending on usage and water quality. For homes with higher water usage and/or poorer water quality, you may need to replace your SmartFlow® Membrane sooner than every 12 months. Stage 4 (Remineralizer) should be replaced every 6 months depending on usage and water quality.

To eliminate the hassle of knowing when to replace your filter, sign up for our Water for Life auto-ship program. Get free shipping, discounts on filter replacements, and an extended limited warranty by joining Water for Life®.

Yes. The SmartFlow® Reverse Osmosis is WQA tested and certified to reduce 90% of fluoride from your drinking water.
Yes. The Aquasana SmartFlow® Reverse Osmosis system is WQA tested and certified to reduce 96% of pentavalent arsenic from your drinking water. It will not convert trivalent arsenic to pentavalent arsenic.
The total volume of the holding tank is 3.2 gallons. Volume is based on your inlet water pressure. So, the gallons in the tank can vary from 1.4-3.2 gallons at any given time.
The SmartFlow® Reverse Osmosis Under Sink Water Filter flows at a rate of 0.8 gpm (gallons per minute).

Reverse osmosis is an incredibly effective method of filtering water, and it works by pushing water through a semi-permeable membrane (a porous block) at a high pressure to remove contaminants. As this pressurized water passes through the membrane, contaminants are left behind and only clean water passes through.

Our reverse osmosis system uses this process, in conjunction with a series of other filters, to increase effectiveness and retain healthy minerals that are often lost during the RO process. Water first passes through our Carbon Block to remove chlorine, taste and odor. Then, the system uses reverse osmosis filtration by pushing water through a semi-permeable SmartFlow® membrane at a high pressure to remove dissolved solids smaller than 1 micron. Next, our Advanced Carbon Block filter uses ion exchange and sub-micron filtration to remove heavy metals, chemicals including herbicides and pesticides, and other contaminants. Finally, our RO system uses remineralization technology to restore healthy minerals like calcium while improving the pH balance and alkalinity of water for exceptional taste.

TDS, or Total Dissolved Solids, is the amount of dissolved minerals and metals present in water. TDS meters tell you the concentration of dissolved minerals and metals, but they are not an accurate measurement for contamination. Aquasana products reduce and remove harmful TDS like lead but selectively retain or replace healthy dissolved solids like calcium. Read more about TDS here.

The SmartFlow® Reverse Osmosis comes standard with a 6-month Remineralizer designed to replace healthy minerals lost in the reverse osmosis process.

Using a reverse osmosis water filter is a great way to remove harmful contaminants like lead, mercury, asbestos, and other impurities that have a range of health concerns. However, it's important to note that the reverse osmosis process also tends to remove healthy minerals from your water as well. To ensure you get the maximum health benefits from your water, make sure to use a filter that has a remineralizer, which restores the healthy minerals lost during reverse osmosis.