iSpring FA15 Alkaline Inline Water Filter Cartridge, 10” x 2” with 1/4” Quick Connect, NSF Certified, Add-on for RO Systems, Balances pH & Restores Minerals, 3-Layer Replacement Filter

Tip 1: Flow arrow is a clear engraving and easy to miss. Don't rely on the sticker label orientation in comparison to the video, which some say can be reversed. Tip 2: My TDS went from about 10-15 (iirc) to about 50-65 (My tap is 400TDS). Perfect for me. This TDS tastes great to me. EDIT: placing in front of tank, TDS dropped to 30-35. Not sure if this will cause scaling in the tank though. Tip 3: Took me about 1 minute to install. It's easy if you know how to release the quick connect. I did it in-line to the tank for now, but understanding there's maybe a few oz in the cartridge that will sit and overmineralize. I'll move it to before the tank if it bothers us as it does for some others. EDIT: I've heard of 3 different ways in the reviews to install this alkaline cartridge lol. The 3rd way is after tank but before polisher. Just different tradeoffs. No one has provided an argument for which is definitively best.

This worked great but only after I flushed the system 3 times. I also changed the other 3 carbon and debris filters too so it could have been those too. After the 3 flushings, the water was excellent tasting! I used this instead filter instead of the apex one on my roes ph75. No issue at all. Same tubing diameter.

I do like the FA15 Alkaline Water Filter Cartridge for the improvement in the taste it makes with my 5 stage APEC RO unit. My initial TDS was about 20 and was about 40 ppm after installation. My raw tap water is about 300-500 ppm TDS. To me, the RO water always tasted a little flat, I usually added a little tap water or baking soda into my glass to make it taste better. Now I find that the RO + Alkaline filter water tastes pretty darned good and the TDS is in a good range for drinking water. The price seems a little high, but compared to the cost of bottled water and the added waste/taste of plastic bottles, it is well worth it to me. Be aware that the faucet output water flow will be slightly reduced. If you enjoy good tasting water, I do recommend this filter. Edit added: Some people recommend installing a filter like this, before the storage tank. I installed mine after the tank, before the final polishing filter to faucet. If you install this after the polishing filter, before the faucet you 'may' get a slight metallic taste.

My faithful Sears RO system doesn't have remineralization and reads pH of around 5.3 at the RO output. Installed this remineralization filter after waiting for 10 days to receive the additional 1/4" -> 3/8" elbow adapters as the Sears RO system has 3/8" output tubing. Tested TPS and pH as the following: Before remineralization filter: pH: 5.3 TPS: 11ppm After remineralization filter: pH (settled value) : 6.4 (initial pH 8.5. pH at 6.4 after flushing output for 20 seconds) TPS (settled value) : 13ppm (initial 41ppm. TPS at 13ppm after flushing) Overall: The pH was increased by around 1.1 after flushing. The overall result is passable if you're going to get a glass or two of water at a time (initial output would be high pH and then starts dropping lower, net pH is perhaps around pH 7). If you want consistently higher pH output you can perhaps install 2 remineralization filters in series. That would perhaps give you an increased pH of 2 (I have not tested this myself). Price has increased so nothing to be happy about on that.

Was worried this product wouldn't work as advertised but it did. I connected this filter after post carbon filter on RO system. Water is also treated pre the RO system with having a water softener with additional sediment filters and UV. Did before and after testing of the RO water. Water becomes TDS 26 from 7 and a PH of 10.01 from 7.20. No noticeable weird taste or smell. Seems to perform as expected. Had to go up a size from filter tubing to supply line to home. Don't know why they choose to have the flow be smaller tubing if you are supposed to attach this after post carbon. My post carbon is the larger size and so I have to down the size and up again.

What you should know about this filter: 1) It works fine, definitely raises PH. 2) You need to install it in a "low flow" situation, probably before your pressure tank. 3) If you install in-line with your RO faucet, you will quickly exhaust it's capacity. I have rain water, which has an initial PH of about 5. Sitting in tanks, PH can drop more and we believe that this can exacerbate some stomach conditions. I've played with it, I'd recommend installing in on the "generation" side of a 75 GPM system, meaning the "slow stream" that produces RO water, typically before the pressure tank. If you install it in-line, this filter simply doesn't have enough media to keep up. Alternately, install 2 of these (using "T" connectors) in parallel and it might keep up on the faucet side... You can see my test results attached.

I installed a reverse osmosis system for my particularly hard incoming water, and although I'm confident in the cleanliness of the output, the taste of that water is a little flat. Turns out, an RO system filters out beneficial elements as well as the bad stuff, and this inline remineralizer filter restores those elements back into your water. Taste can definitely be subjective, but this filter makes my RO water crisp and tasty.

If you're serious about coffee, you know that water quality is everything. This iSpring alkaline filter doesn’t just clean the water—it enhances it. By restoring essential minerals and balancing pH, it gives my coffee that perfect, clean taste every single time. Installation was a breeze thanks to the quick-connect system, and maintenance is simple. I can confidently say that since adding this to my RO system, my espresso shots taste smoother, and my customers have noticed the difference! Plus, iSpring’s customer service is next-level—Nicholas personally made sure my system was running perfectly. If you own a coffee shop, this is an absolute must for consistency and quality.