iSpring F9K NSF Certified 1-Year Reverse Osmosis Water Filter, Alkaline Remineralization Filters for 6-Stage RO Systems, Without RO Membrane

Super system at this price! We've bought it years ago. Of course, the filters fit. We installed the iSpring reverse osmosis set a few years back. It is well worth it's money by now. Water from regular interval filters tastes good to me, and I am sensitive when it comes to water's taste. Can't drink odd or off tastes without cringe. I like arrowhead though not in ecstasy about it, not ok from plastic bottles stored in hot weather except in emergencies. I like some mountain streams and some wood springs, am ok with occasional, light carbonation - though it won't improve the taste, just change and mask it. We also used different $15-30 test strips on occasion throughout the house and this water's our clean baseline. I hate chlorine taste and feel and do not want more iron or lead or PFAS than necessary, either. There's only so much antioxidants can do for us. So, despite the terrible fact that this system wastes 2x the amount of water you get from it (wish we could rig it so the excess watered our garden or plant) - this is totally worth it to me. I try to meditate when filling a bottle to put in the fridge for the day, it takes about 20 seconds. It's not so bad with just a glass, but it also isn't for the super easily annoyed. Our storage canister, which is slowly refilled with pre-filtered water after you tab out some, is great for two or three people to drink and cook. If you need a lot of water at a time, you might require a larger system. Think of the time saved hauling and trashing bottles, that gives ample patience and glee to the adults at least. Installation is a bit tedious but straightforward enough. And here's a secret superpower: iSpring's customer service is actually super friendly and helpful! After some years the system started dripping (to refill the reservoir) and just didn't stop unless we turned off water. Called CS and they helped us troubleshoot successfully. Yey! If you have no savy at all, get someone to install this for you and set a reminder to replace filter cartridges on schedule. Especially renters profit from the compact and relatively easy system, it takes some space but leaves enough of room under our double sink for two small trash bins and detergents. The shower's got a cheaper filter (which won't waste) and I would NOT drink that water. It's just barely ok on the skin. This water quality's actually impressive given the price of this system is in the low hundreds. Even disregarding eventual medical bills you prevent, you'll save that back financially by just stopping to shop bottled water. We get solid bottles and just refill, wash, refill for up to a year of reusable, high quality plastics or years on end with stainless. Health, economy, even ecology benefit (considering this set lasts us years now and we used to buy plastic bottles, made with a lot of damage to water) - We're very happy.

I purchased this system in February 2018, I wanted to wait a while to see how it performed before writing a review. I have a background in water quality and am a bit of a water snob so I had very high expectations for quality and the water it produced. Installation was great, they include everything you need to install it on existing equipment. It attached to the cold water angle stop for your sink, they have a nice brass t fitting that will adapt to whatever you have under your sink either 3/8 or 1/2. it included an isolation valve so you can easily turn off your filter system for maintenance and carriage replacement. As a plumber I was very pleased with install. I am very picky in the way I put things together and it still only took me about an hour or so. I bet you could do the job in 30 minutes if you were in a hurry. Parameters: my tap water has any where from 250-400 ppm total dissolved solids (TDS). That's pretty standard for municipal water in southern California. still that is allot of stuff dissolved in the water including lead, arsenic, chloramine, and trace chemicals. Ph from tap is about 7.8. Coming out of the RO membrane before it hits the Alkaline cartridge I got a TDS of about 9-14 ppm. That is pretty incredible. the finished Alkalinity from this system was 8.8! perfect alkaline water. the mineral content was a great also, about 40-60mg/L of Carbonate hardness and 60mg/L general hardness. That means the perfectly minneraled and alkalized water free from chemicals, heavy metals or any harmful contaminates. The flavor as you can imagine is incredible. I use it to brew beer with, my friends cant believe the quality of my brew, the secret is the water. I use it to brew kombucha with similar results. I use it to fill my fish tanks, the African Cichlids need the high Ph. Finally the customer service for iSpring is impeccable. I bought a cartridge replacement and has some issues, customer service was quick to handle my issue and did not cost me a dime to make it right. these are the genuine replacment filters and they make the system work as it did the day I installed it

We have had the I-Spring 6-Stage RO for 1 year and we absolutely love it. We would never go back to non-RO water. We use it for drinking, cooking, canning, coffee. We even give the dog RO water :) I recently hooked it up to our fridge so we can get RO ice cubes. Our old ice cubes used to stick to each other all the time even when they were freshly made. As soon as we switched to RO, the ice cubes don't stick and are noticeably better - who would have thought! This filter pack is expensive, but we still think the value is exceptional for this system. You get 2 each of the filters (except for the stage 5 carbon filter because it lasts a year). So that's 9 filters in all - a little less than $10 a filter. The filters all appear well made. The old 1st Stage filter was really gross when I took it out, it had a color between sand and iron. We are SO happy that we did not drink any of that stuff. The flow rate also improved noticeably after the filter swap. I waited an entire year before swapping (you are supposed to do every 6 mo). Next time I will probably do it closer to 6 mo. The filter swap out did take some time. First you have to shut off the valves, release the pressure, unhook the flex pipe, and pull the unit out. I put aluminum foil over the tubes that had the clean water running through them. Remember that the RO water is untreated so it's important to keep contaminants away from the parts that touch the RO water. The 3 tanks on the bottom are very easy to unscrew and replace the filter (provided you have the tool), but the carbon and Alkaline filters are more difficult since you have to unscrew all the connectors, take apart, and then put back together. Again be careful to wash your hands and don't contaminate the last 2 filters. Don't forget to run an entire tank through the new filters before use. Also a general note, don't forget to completely drain the tank when you let it sit idle for a 5 or so days. I've noticed it tends to get an odd taste, which I assume comes from the tank. They also say to refrigerate the RO filter if you will be gone for more than a week. I have not done this yet, but I think I would just throw the whole unit in there instead of removing the RO filter (and place aluminum foil on any open tubes).

I have been running a 6-stage reverse osmosis system for a year, and while RO water is incredibly pure, it can often taste "flat" or become slightly acidic due to the removal of all minerals. I chose the iSpring F9K 1-year replacement pack specifically for the Alkaline Remineralization stage, as I wanted to restore the essential minerals and raise the pH to a more "natural" spring-water level. Filter Quality & NSF Certification • The Build: These aren't generic "knock-off" filters. You can feel the weight difference in the high-capacity sediment and carbon blocks. The fact that they are NSF/ANSI certified provides peace of mind regarding the safety of the materials used (no lead or BPA leaching). • Remineralization Stage (AK Filter): This is the star of the pack. It uses red mineral stones and calcite to add calcium, magnesium, and potassium back into the water. In my testing, it successfully raised the pH of my RO water from a slightly acidic 6.5 to a much more alkaline 8.2. • Carbon Block Efficiency: The 5-micron CTO carbon block is exceptionally dense. I noticed an immediate removal of the slight "chlorine" scent that had begun to creep into my system as the old filters reached the end of their life cycle. Installation & Fitment • Standard Sizing: These are standard 10-inch filters. They fit perfectly into my 10" housings with no "bypass" issues or rattling. • O-Ring Integrity: The seals on the sediment and carbon filters are high-quality rubber. I didn't experience any of the "crimping" or leaks that sometimes occur with lower-tier replacement packs. • Flushing Process: Every carbon filter requires flushing to remove "fines" (loose carbon dust). I ran the system for about 10 minutes, and the water cleared up significantly faster than with previous brands I’ve used, indicating a cleaner manufacturing process. Pros & Cons ✅ Pros: • Comprehensive 1-Year Supply: Includes all pre-filters and the specialized alkaline stage (minus the RO membrane, which usually lasts 2-3 years). • Superior Taste Profile: The remineralization stage gives the water a "crisp" mouthfeel that pure RO water lacks. • System Protection: The high-quality sediment filter does an excellent job of protecting the more expensive RO membrane from clogging. ❌ Cons: • No Membrane Included: As the listing clearly states, this doesn't include the RO membrane. Ensure you check your membrane's age before ordering just this pack. Final Verdict The iSpring F9K is the gold standard for maintaining a 6-stage system. It doesn't just "clean" the water; it "engineers" it for better health and taste. If you value consistent pH levels and want a certified filter that won't leak or bypass, this is a necessary investment for your home’s water quality. Helpful? If this breakdown of the pH levels and filter density helped you, please click the "Helpful" button below!

The filters are good quality and not too difficult to replace in my RO system. Overall, I have been very happy with my iSpring system. However, after today, I can vouch that their customer service is also top tier! I ordered this one year supply during prime day deals and should have opened the box right away. However, I didn't because they weren't due for changing yet and I found the box that Amazon sent was missing 3 of the filters. I went ahead and placed another order so I had them, but now I have an odd assortment of filters. I called iSpring's customer service line and talked with Nick and he is going out of his way to help me get the missing filters replaced. This is 4 months after my initial order (and I think it was more of an Amazon issue not iSpring) so he would have been well within his rights to tell me I am out of luck but he didn't. It is hard to get that level of customer service these days so I appreciate it and I will spread the word about their products and customer service from now on! Thank you, Nick!

I’ve been using this 1 year reverse osmosis filter set for a while and it does an excellent job and keeps the water nice in my 6-stage RO system. The NSF cert is reassuring for knowing the filter quality I can expect, and I have experienced clean clear good tasting water ever since I put these filters in! The alkaline remineralization really does put back some nice minerals and I’ve noticed the water is more tasty than the plain RO filtered water. The filters are well-made and fit perfectly into my system without leaking or any other problems. The only thing that I find sort of a pain is that it’s hard to tell which specific filter is which until you open up the individual plastic bags - some are very similar looking, and the outside packing is not necessarily clear concerning which bag has which filter. It would be much better if they each sealed bag had some clear printing on it of what type of filter is inside it, and the stage number it belongs to. Occasionally, I have to open one up just to make sure it’s the right filter, and that is a bit annoying at replacement time. Overall, each filter works like it should and lasts the whole year as advertised! Worth the price and it was easy to replace. It is compatible with my iSpring 6-stage.

We bought this filter set to go into the ispring RO system we installed in our house when we moved in. We had one of those expensive 3 stage 'professional' systems at our previous house and it was a pain to get filters for it. Could only get them from that company. This is so much nicer, and if I'm honest, the water that comes out of this system is better tasting. Money well spent.

I ordered the replacement filters for my new iSpring Reverse Osmosis and they came in a timely manner. This was my first time replacing them and it wasn’t as easy as I thought it would be. I believe the filters were tightened too much at installation by the plumber and I had to open several faucets and run water for a min or so, and also apply heat from a hair dryer to get the first one off. After that it was fairly smooth and I also used the You Tube video tutorials for help. The problem came when the alkaline cartridge appeared to be mislabeled with regard to the direction of the water flow and the label on the filter lined up. The label was probably put on upside down and the direction of the arrow was how I lined it up. I had been on the phone with Nick from the support team and he was helping guide me through the installation process. His help was very much appreciated and he answered all my questions, suggested the hair dryer and opening faucets, etc. When I turned on the water, it went everywhere. I saw it coming from the connection at the end of the alkaline filter. I quickly shut it down and called for support. NIck had another alkaline filter and fittings expedited to me in the advent that there was something wrong with the one I used. When it arrived the plastic fittings were broken. I had scheduled the plumber anyway, and he came and put it together, and showed me how the little blue sleeves or collars fit around the end of the filters, and explained the reason for them. Nowhere in the written information was this addressed so that I could completely understand it. In the video it was just mentioned to put them on the end, and no close up picture provided an accurate view with exactly how/where they were to be placed. The person’s fingers partially obscured what he was doing. After the plumber explained the function of this part and showed me exactly where it was to be placed, I understood. I would never have intuited that it go where he put it and then was loose enough to spin around. I would have placed it further away on a segment where it would fit tightly (again, not knowing what it was really for). This is a problem I find with instructions to a lot things. The “simplest” things are omitted maybe because they are thought to be so simple and plain, as to be unnecessary. Not so! A big improvement the company could make for people like me with no plumbing background, would be to thoroughly explain that tiny little part that is ultra important to the correct functioning of the system. Probably time to make an updated video because now all of the fittings are quick connect and do not require taping the ends, as the video explains. This was also a bit confusing. Anyway it works now and the water tastes great! I would highly recommend the iSpring Reverse Osmosis water filter system, especially with the mineral replacement cartridge! UPDATE. There was explanation for the plastic “collars” but it was in the beginning installation instructions. I did not install my RO and so, went straight to “maintenance”. I saw no clear explanation there, so for anyone looking for directions, they are in the first few pages of the manual. A lot of detail in the installation portion! My eyes crossed and so I went straight to maintenance 🤣.

Me gusta la calidad de estos cartuchos de repuesto, además que son más fáciles para cambiar en la purificadora.

خاضعة للمواصفات الامركية انصح بها لمن يبحث عن الجودة 👍

Ho acquistato il set di cartucce iSpring F9K come ricambio annuale per il mio sistema di filtrazione, e la differenza si sente subito. Dopo l’installazione, l’acqua è tornata chiarissima, senza odori e soprattutto buonissima da bere. Il montaggio è semplice e tutte le cartucce si inseriscono senza difficoltà. Anche il flusso dell’acqua è rimasto costante, senza cali di pressione. Per l’uso domestico quotidiano è un kit davvero completo e conveniente, perché permette di coprire l’intero anno senza dover acquistare filtri singoli. In sintesi, sono ricambi affidabili e fanno esattamente ciò che devono: migliorare il gusto dell’acqua in modo evidente.

Très bon système de filtration d’eau très satisfaite j’achèterais de nouveau. Bon service aussi le robinet coulais et la cie à régler le problème rapidement. Très satisfaite. Jamais goûter de la bonne eau alcaline comme celle ci.

Buenos repuestos para mi máquina de osmosis. Buen sabor del agua. De momento estoy muy contenta con la compra y ya llevo más de 6 meses