3 Gallon RO Expansion Tank – Compact Reverse Osmosis Water Storage Pressure Tank with Free Tank Ball Valve

Good product

Easy to install, good quality and works like a charm. Much cheaper than getting a replacement through Kinetico.

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!

First - it's a tank (though a big one). Not much to it. It's almost life changing to have this much drinking water available with this much pressure. Absolutely loved the past 2-1/2 years. Unfortunately - the happy time came to an end. Water tasted rubbery yesterday - I suspected the cause but didn't want to deal with it. Today I finally went under the sink and tested the air valve - yup, out spurted water. Means the bladder ruptured and the tank is shot. Note to others - if you have any RO system with any tank, new or old, and the water tastes rubbery or you have spurts of air from the dispenser, odds are the tank has failed. Easy check - just unscrew the air valve cover (if present) and press on the stem. If water comes out - the bladder has ruptured. Replace the tank. What to do? 1-year warranty - and it's been 2-1/2. I don't see anybody with a 5-year, let alone a lifetime warranty, so does it matter? This one says it's coming from Taiwan. The others are China. I'm biased - I'll order another of these. Hope this one lasts longer.

I’ve had a RO system for many years and had a smaller tank on it. The bladder finally went and I decided to upgrade and it is performing very well. I followed the instructions to clear the tank after one minute of operation and then again after four hours of operation. There is no residual taste. When hooking it up to your system, I would make sure to just leave the pressure where it’s at as it is typical for most systems. If it doesn’t work for you then adjust it. Furthermore, when you put the Plastic valve on the top, I would use not only Teflon tape but also some dope as well. I had to return the first tank they sent as it was not wrapped well and came dented, but to be fair it did work for the short period of time before a replacement was sent, the company was quite responsive. As an FYI, the second tank came much better wrapped. It was undamaged. they had clearly realized they had a problem so they change the wrapping.

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.

Update: this tank eventually failed possibly due to high incoming city water pressure ( I was not using it with an RO system, just a regular carbon filter). I contacted the seller and in less than an hour they made everything right and also gave helpful advice to prevent any future problems. THANK YOU! If you are using an RO system without a pressure tank like this one, a 1/4" line takes a couple minutes or longer to fill a 2L jug. With this 3 gallon it is now so much faster to fill a pitcher. 15 seconds instead of several minutes. This is a small purchase but it really solved an annoyance of waiting for filtered water. I flushed it one time before I drank from it, and have not noticed any odors or sediment at all. Big bonus points for having the quick connect valve included, it is a cheap part but if sold separately will set you back 5 or 10 bucks.

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.

I ran a new line to my fridge's water dispenser and ice maker from my existing 3 gallon reverse osmosis system. The existing tank was barely enough to keep up with my family of 4, but this will help supplement. It was installed in parallel with the other tank. The tank comes with a 1/4" tank valve. My existing system is mostly 3/8" so I had to purchase an extra valve for it. Pros: the tank came pre-charged to 7psi. I received a 6.5 gallon tank instead of 6. The tank was a nice blue as pictured. Cons: the tank came with a dent at the top.

Tank size is us gallons but distributor is in Canada. I had to go else where for equivalent imperial size.as capacity which worked great & delivered water for a larger household.

If you have RO water it’s nice to have the big tank for storage, most RO makes lots of water but has minimal storage

The tank I had on my pump was too small, so my pump was always starting. I installed this big boy and now I can take a shower without it starting. Other than the possibility that the inlet may have a smaller pipe than your present tank, necessitating the purchase of a couple of pipe fittings, this tank is the answer to your problem. Don't forget to inflate the tank to withing two pounds of the kick-in setting on the pump. 24 p.s.i. is fine on such a big tank. The air pressure valve is under a 1" cap on the tank. Enjoy

No good. Bladder in tank ruptured in less than a year. The tank is now useless and I can’t get customer service to help me not worth it. Money water coming out of the air valve.