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tankRo

GTS3 3 Gallon RO Water Filtration Expansion Tank, Compact | White Finish, Includes 1/4" Ball Valve, Durable Steel Construction, Universal Fit for RO Units

  • Based on 1,389 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, Aug 5
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Size: 3 Gallons


Features

  • Reverse Osmosis Tank: Made from 100% food grade materials, this RO water tank stores and keeps your water free from any impurities and harsh chemicals. The perfect addition to any RO water system.
  • Easy to Install Water Tank: RO tank replacements include free tank ball valve for easy set-up and replacement with 14 quick connect design.
  • Durable Water Storage Tank: This RO water tank is rigorously tested for quality and durability and includes a 1-year warranty.
  • High Quality Water Tank: This water storage tank is made from durable deep-drawn steel domes with precision welding to ensure long lasting value for your RO water system.
  • Water Tank Dimensions: This compact water tank is designed (14 x 9 x 9) to fit under most kitchen sinks. Stores up to 2.2 gallons of water for on-demand filtered drinking water.

Description

Have the best water for your house with Express Water's reverse osmosis and whole house systems! Express Water offers replacement filters and filter sets suitable for many reverse osmosis and whole house systems. Express Water is proud to be a charity: water supporter. 100% of public donations go directly to clean water projects. Visit the Store Your Water: Safe and Healthy The tankRO 3 Gallon Water Tank is made from the best FDA graded materials and is designed to ensure your water remains as clean, contaminant free, and pure tasting as when it entered. -All Materials in the expansion tank are 100% food safe and FDA grade to make sure your water is tasteless, odorless, and contaminant free -The inside of the RO water tank is completely smooth to prevent damage to the bladder -The water storage tank is coated with a two-part epoxy primer and finished with polyurethane to resist damage even in the outdoors -The adjustable bladder within the water tank is made of high grade Chlorobutyl rubber and is completely airtight -The inside liner of the water filter tank is made of Virgin Polypropylene, the most durable liner even on a molecular level A 3-gallon water pressure tank can hold 2.2 gallons of water. All tanks have a certain amount of their capacity used by the air bladder, which is necessary for drawing water from the water reservoir tank. A free 1/4" tank valve is included Compatible setup for quick connect tubing Comes with a tank stand to secure the tank All components are high quality food-grade -Each RO tank passes extensive durability testing -A sealed brass air nozzle and o-ring sealed air valve caps means consistent air pressure -This reverse osmosis tank is designed to last over five years

Brand: tankRo


Special Feature: Durable


Product Dimensions: 9"L x 9"W x 14"H


Material: BPA Free


Capacity: 3 gallons


Included Components: Tank


Package Information: Tank


Installation Type: Under Sink


Purification Method: Reverse Osmosis


Power Source: Adapter


Other Special Features of the Product: Durable


Container Type: Tank


Installation Type: Under Sink


Purification Method: Reverse Osmosis


Power Source: Adapter


LowerTemperature Range: 33 °F


Maximum Flow Rate: 0.8 gpm


Operating Pressure Range: 5-100 psi


Upper Temperature Rating: 100 °F


Supported Water TDS Level Maximum (PPM): 2000


Item Dimensions L x W x H: 9"L x 9"W x 14"H


Capacity: 3 gallons


Item Weight: 6 pounds


Brand Name: tankRo


Included Components: Tank


Model Name: GTS3


Model Number: GTS3


UPC: 653590999287


Manufacturer: tankRo


Unit Count: 1 Count


Part Number: GTS3


Material Type: BPA Free


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Aug 5

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Hi, quality product top-notch.
Size: 6 Gallons
If are struggling with low pressure? Intermittent working and slow water from the osmosis system, this is the way to go. This reserve water tank was the answer to my problem. The installation was easy, a filtration system through that is absolutely no problem. Whatsoever value for your money is on top. You can't beat the price. It is cheaper than trying to have somebody come out. And go through the system, as for the quality of the tank, it is top-notch. ... show more
Reviewed in the United States on July 1, 2026 by John Valdez
    • Works great
Size: 6 Gallons
Works as described
Reviewed in the United States on June 27, 2026 by john
    • Perfect fit
Size: 3 Gallons
Fast and simple. My old tank had a bladder failure and needed to be replaced. The new tank came with the top fitting, but I drained and removed the old tank and slipped this one in without any issues because the fittings were the same.
Reviewed in the United States on June 22, 2026 by Adolpho
    • Add Extra Water Capacity to RO systems
Size: 11 Gallons
Review Image by Nicholas G.
I used this to adapt the tank to my current expresswater RO system. EZRODI 2 Pack RO Water Tank Valve Connector for Reverse Osmosis Storage Tank (2, 3/4 in. Female Thread and 1/4 in. O.D. output) https://a.co/d/j7VZGUK. Then I used a Y John guest fitting to connect both tanks in series. Don't listen to the instructions. Says takes 3 to 5 hours to fill tank. NOT TRUE, took the entire day, you're splitting pressure among to tanks and increasing real capacity to 11gallons+. Be patient and let the system do it's thing. Check your tank pressure on the tank, if it's below 10 psi fill it to 10 psi. If the pressure is too low the system will continue to discharge and not close the the valve after tanks fill up. No one, I mean no one in any of the reviews or forums could figure this out. I had to trial and error to find this solution. I see many people complain about continual water discharge after 3 to 5 hours of letting your system tank fill. If your system is new or you have new filters it is the tank pressure. To test the stop valve you can close the tanks from the the system, if the water stops discharging means your valve is working. Tank is super high quality and tank bladder was at correct pressure (10psi). EXPRESSWATER is a fantastic company. ... show more
Reviewed in the United States on December 17, 2023 by Nicholas G.
    • Good tank, bad hardware
This is a perfectly nice tank that is let down by the crappy hardware and fittings they installed on it. Which is unfortunate, because I wouldn't have faulted it at all for coming with NO hardware, even if it was the same price. But who wants to undo and re-do somebody else's work? The tank has a big plastic foot with a hole for the pipe. It can be installed in six positions depending on how much you have to turn the elbow on the bottom to get it to seal. Don't even bother with anything they did. Remove the whole foot, and remove the elbow. The cheapo elbow had a giant burr in the threads and didn't seal. In order to get a wrench on it you have to remove the foot. And once it's tight it's not going to be pointing the same direction it was before anyway. There is an additional chromed fitting with a dramatically undersized ball valve too.... plan on just tossing those. I _know_ it's hard to source quality stainless NPT elbows these days. But if they're going to buy garbage ones, they should at least chase the threads and/or pressure test after assembly. ... show more
Reviewed in the United States on May 10, 2025 by J. B.
    • Ditch that small tank for this - you will be glad you did. SO. MUCH. WATER!
Size: 11 Gallons
Original RO system came with a paltry 3 gallon tank, of which only 1.8 gallons was for water storage. I didn't know how awful that was until the membrane in that tank died. Determined to ensure we always have enough RO and plenty of pressure in the line, I doubled the desired capacity, and then DOUBLED it AGAIN. So, the 8 desired gallons of liquid required a 10-12 gallon tank. The tank came with ZERO installation hardware. I stole the old valve from the old tank which worked out just fine. By morning, we had 8 gallons of RO water flowing. I strongly recommend this tank! ... show more
Reviewed in the United States on September 11, 2025 by Brian Shensky
    • Water treatment storage tank
Size: 6 Gallons
This was a perfect replacement for the original storage tank for my pressure-based RO water treatment system.. Even has more storage capacity than the original.
Reviewed in the United States on April 20, 2026 by DST
    • Failed in 4 months
Size: 6 Gallons
Failed in 4 months. I purchased this on October 30, 2025. It is March 29, 2026 and the unit has failed and lost pressure. I cannot be repressurized because the internal bladder is leaking. Poor quality. Poor value for your money.
Reviewed in the United States on March 29, 2026 by squinting to read...

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