Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Fixing Brown Rusty Water (Excess Iron) in Swimming Pool Water

Quickstart:
Well water and city water often contain iron which is dissolved & invisible because the water is slightly acidic. As soon as you add chlorine (very highly alkaline), the iron precipitates as 'rust dust' or brown water.
In-ground pools usually have good filtration which, given a little time, will correct the problem. Above-ground pools often have no filtration or minimal filtration so the problem can be serious. One approach is chemicals like 'iron-out' which try to chelate the iron, keeping it dissolved, but the iron is still there so it's a temporary solution. The better approach is filtering out the 'rust dust' with one of the many very simple home-made filtration systems described here by readers.

14995-2 14995-4 14995-7
At start, then 9 hours later, then 24 hours later -- courtesy of Jenna Bradford

A. Use floc'ing. It will make the rust settle to the bottom and you can them vacuum it up.

Lily McG
- Texas
July 2, 2022

A. I have had this problem for years. it takes a few days but just leave the filter running and it will clear up. Backwash often. It's really not a huge deal. The filter will clear it up.

Donnie Trail
- Rocky Gap, Virginia
May 24, 2023

A. I had the same issue with iron. It took me a few years to figure out it wasn't algae ... and it was only the "luck" of a rainy pool season in 2022 (upstate NY) that identified the real issue. Because it was so rainy, I went almost the entire season without adding water to my pool, and never had the dreaded brown water. At the end of the season I did need to top off a bit from the hose, and a week later I had brown water. Because it wasn't immediate, i didn't take the correlation.
When I opened my pool this season, I had more than enough water from the snow melt to start out, and I went weeks with super clear water. First time adding water from the garden house, I was good ... until a week later when I shocked it. And it was brown the next day. Turns out the chlorine oxidized the iron in the water that I added from the hose, and made it visible overnight.
I did some research and tried a few things. The best was a product from Regal called "stain out" ⇦this on eBay or Amazon [affil links] The label reads as if it is more for iron stains on your liner, but some Google info said it would treat the water as well. Folks ... I added this at the recommended rate for "severe stains" which was 1.25 lbs per 10,000 gallons. I literally went from brown water to crystal clear (blue looking due to liner) in 20 minutes. Try it. You won't be disappointed.
I'm going to try lower doses next time and see what works and what doesn't. It isn't great about listing the chemicals on the container, but it does call out sodium sulfite and sodium erythrobate ... just in case regal is not sold in your area and you need a comparable.
I hope the helps someone else with this issue!!

Ken Gregory
- Schenectady, New York
June 1, 2023

Q. How can I fill up my inflatable pool with well water without the bottom of it having black particles in it?

Catherine
- King, North Carolina
July 23, 2024

Ed. note: Since 1989 this forum has enjoyed the camaraderie & warm aloha which real names & locations afford. If you're not into that spirit, those who do post with their real name may be less likely to engage with you.

A. Hi Catherine,
Other readers have suggested a simple hose-end filter ⇦this on eBay or Amazon [affil links] . While I think it would probably be exhausted long before a large in-ground pool was filled, it would probably be just fine for a blow-up pool.
Luck & Regards,

ted_yosem
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

⇩ Related postings, oldest first ⇩

Q. Help! We just put up and filled 15 x 15 x 3,5 pool and filled it with about 4,646 gallons of our terrible town water which is full of iron! We have tested it, shocked it, tried clarifier and still have the brown rust. Do I just keep shocking the thing until it disappears (if ever)?

Barb Hand
- Carpentersville, Illinois
2002

Editor's summary: Readers are welcome to read this entire long thread if they have the time. But dozens of users found themselves able to easily get from brown rusty water to a sparkling clear pool with simple home built filters ranging from a couple of white socks to a pair of 5-gallon buckets with a small sump pump in one and the stuffing from a couple of old pillows in the other. Jump to first home-made filter posting.

"What Color is Your Swimming pool?"
swimming_pool_color

on AbeBooks

or eBay or

Amazon

(affil links)

A. Stop adding chlorine! Until you remove the iron, the water will stay brown. You're wasting your time and money. Go to your local pool store and bring a water sample with you. They should be able to test it and tell you exactly what to add to your pool water. Most likely it will be with what the pool store calls "pool magnet". I just had the same problem and it took me about 3 days to turn 10k gallons of water from dark brown to a light green blue. My next step is to get the water clear. However, my pool store told me to wait at least a week before I add any more chlorine. Hope this helps. Have faith in the pool store. Yes, they are more expensive, but you get it done right the first time, which in turn saves you time and money.

Regards,

Joe Sorbellini
- Mt. Tremper, New York

A. Here in the Algarve we have the same problem with borehole water, but we do the following.Shock the pool to oxidise the iron out of solution and into floating sediment. Then add flocculant to cause all the particles to lump together and sink to the bottom.This we do with the pump off at night as the sun causes currents that disturb the settling process. This lasts 8 hours.Then we vacuum out the rust from the bottom of the pool. I hope this helps.

Philip Dalston
- Algarve, Portugal

Natural Clarifier
natural_clarifier

on eBay or

Amazon

(affil links)

A. We just got a 18 foot blue Intex pool and have the same brown water after shocking it. After spending a ton of money trying to get the water clear, I finally found something that is working. I got a chemical called Super Quest (made by Sun). It eliminates and controls iron, copper, manganese, staining and discoloration. I poured it all around the outside of the pool and then added a Natural Clarifier ⇨
right to my skimmer.

Every 1-2 hrs I took out the filter and cleaned it. After cleaning the filter I added more Clarifier to the skimmer. If you don't have a skimmer, add it right next to where the water goes to the filter. My water is looking much better. I still have a little ways to go but it's getting there. I hope this helps!

Krystal Palmer
- Lindstrom, Minnesota
July 25, 2006

? This question is in response to the post by Krystal P in Lindstrom, Minnesota. You mentioned a product called Super Quest for your pool. Where did you purchase this product? I can't seem to locate it. Any help from anybody would be appreciated. We can't seem to clear up our pool and the water is full of rust. Thank you.

Richard Guedon
- Punta Gorda, Florida United States
February 17, 2017

A. Hi Richard. The product Krystal was referring to was "Sun Super Quest". I appears to no longer exist, but there are similar products. If you want to find one which is as close as possible, there is a Safety Data Sheet which tells you what was in it:

~~http://appatek.com/MSDS/SUN/Super%20Quest.pdf~~ ⇩

Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Ed. note: Sorry, that link no longer works, but archive.org's terrific Wayback Engine finds it for us.

Q. Where did you buy the Super Quest? I can't find it?

Rena D.
- Bark River Michigan
July 28, 2022

A. Hi Rena. This was a product of Asepsis, Inc., Suwanee, GA, dba Sun Pool Products which currently seems to be out of business. But there are dozens of pool chemical suppliers offering similar products. You can find out what was in it with the Wayback Engine.

Luck & Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Q. Hello I have terrible well water, lots and lots of rust. We were told that our salt levels were way too high and need to drain our blue pool more than 1/2 and add new water. Our problem is that our water is so bad! I added it and the pump has been going like crazy. It has been two days and the water is still very brown so much you can hardly see the bottom. We have Jandy salt generator. Should I shock it even know it is salt water? Also we have had two different pool companies taking care of the pool for us, neither of them knew how to take care of a salt water pool, I would see them ad a chlorine tablet. Should they have used chlorine in this type of pool. I want to start taking care of it myself but am unsure on how to tell when salt is needed, or any other chemicals if that. Thanks for any info.

Super Simple Home Made Filtering

A. Have a good and inexpensive solution that worked for us. Take a white bath towel and hang on the steps to your above ground pool, directly in front of the pump discharge line in the pool. The white towel does catch the rust. Let it hang there for a couple of hours and then remove towel and hose the rust off the towel and repeat. We even let the towel collect over night and rinse it off the next day. Keep repeating as you have time. Yes, you have to keep running your pump to do this, but it will get the rust out. If you don't believe it, just give it a shot one time and you will be amazed at how much rust loads up on that towel. It took us a couple of weekends and once or twice daily during the week (we have jobs) but worked better than any chemicals that the local pool supply folks suggested. Continue to check your cartridge filter and clean it out as well; it doesn't do nearly as good a job of collecting the rust but it will collect some and needs to be cleaned out as long as your water is heavy with it.

A. To increase Intex paper filters effectiveness, build your own filter. A real quick fix is an old cotton sock placed over the strainer basket in the skimmer. Stuff the toe end down inside the basket. Add higher levels of chlorine to release the iron and watch the socks turn brown.
Remove socks, wash out and reuse. Continue until pool loses its green tint and turns blue. Works for smaller pools.

A more complex iron filter can be made by drilling 1/4" holes in the bottom of an old 1 gal milk jug, pack it tightly with pillow / teddy bear stuffing (the white polyester stuff at Wal-Mart) and attach to the return hose inside the pool. If you have the Intex skimmer, the hose fits the neck of the milk jug perfectly, just secure with a zip tie or hose clamp and move the hose to the return fitting instead of the output. Keep flushing out the iron with fresh water when it gets brown, or toss the jug and make another one. Only takes a few hours to see a significant improvement.
When you're done, shock and enjoy the clear water.
Filtering the iron out is better than sequestering it; the iron is still there, you just can't see it.

Well, here is a great solution to your iron (in the pool) problem.
I just used this pre-filter. Many pool/spa stores have it for about $ 20.00. It attaches to a garden hose and then you just fill the pool or spa with any kind of water. You can get more info from the link.
~~www.hottubessentials.ca/1-micron-spa-fill-filter.asp~~ ⇩

Lady Ponder

I was so thankful to stumble onto this forum. My first thought was to try Iron Out ⇦this on eBay or Amazon (affil link)] , but it sounded a little dangerous to me. After reading further, I realized I couldn't try the iron out or the Oxy Clean. I wouldn't be comfortable swimming in these chemicals, so why would I let children? I was so relieved to hear the simple method of putting the towel in front of the filter. I had instant results. I cleaned out the filter, placed the towel in the water, and in about four hours, I could tell a dramatic difference. Thank you!

So I combined two techniques on here into one and am having AMAZING results. When I say amazing, my pool is 10 shades lighter in color than it was this morning. You see, I thought I had algae and started shocking the heck out of it! Just made the water browner and browner. Anyway I used the cotton sock inside the filter housing and all that jazz and instead of a white towel in front of the discharge port a Child's cotton tube sock fits snug enough to not get blown off and let me tell you!

I have washed the socks out three times now and the pool is making DRASTIC IMPROVEMENTS! You can go spend money to solve this issue or you can save money for the gas tank and use those socks that the Gnomes pilfered partners from. Trust me, THIS SOLUTION IS AMAZING!

A. Unfortunately, I've learned more about this than I ever wanted. Three years ago we moved to an area where our only water source is well water. The first year, I filled our pool and it was so dark and brown you couldn't see the bottom. I did lots of research and discovered a product called "Slime Bag". This bag fit over the water return on my filter. After the first couple of hours, I saw a remarkable difference. I removed the bag, rinsed it and repeated. Within 2 days, my water was crystal blue. The following year, I used the "slime bag- filler up bag" while filling the pool and put another on over the water return on the filter. Water was clear within 2 days of filling. This year, I tried another approach because I wanted to avoid buying another slime bag. So, I simply filled the pool 1-2" per day for 1 hour per day. The water was just barely cloudy and I was elated. I thought that the problem with the iron had been solved because we had replaced the filter and pipes on our water pump. However, two days after filling the pool and letting the pump run, the water remained a little cloudy. So, I did a shock treatment and within minutes my water turned reddish brown. So, I'm back to using my slime bags on the water return. Once again, it is working. It takes a couple of days but seriously, putting Oxy Clean or Iron Out in the water just sounds really scary.

The slime bags actually remove the iron so that you can add chlorine the rest of the summer without any problems. I have never tried the sock or towels, but I may give them a shot as well. If they will work, it would definitely be cheaper than the slime bags!

A. Ok I have had this EXACT problem. We have an intex pool, and I really wanted to throw it in the trash but then we GOT IT RIGHT. We have well water also. Every time we shocked it turned yucky BROWN. The pool guy says it is excessive metals in our water. So we drained the pool, this time filled it back up with water but on the end of our water hose we used several coffee filters and the sock's secured tightly around the end. I got this advice from neighbors...
I'm assuming it helps filter the water. When the pool completely filled we put 3 bottles of metal out in it. We also upgraded the paper filter with a better one we got from the pool store. Waited three days then bought liquid chlorine (kinda a light green color) and my water is beautiful. The pool place told me not to shock it with the powder shock that comes in the bag just to use that, and so far it is PERFECT.

Q. I joined this discussion in a somewhat-desperate search on Friday night. 24 hours before my home/garden/pool was to be on our community's Garden Tour, my pool heater burped rust into my newly-sparkling pool and turned it into a chocolate brown.

I found this discussion. I tried the oxiclean ⇦this on eBay or Amazon (affil link)] route (any port in a storm, 9 PM the night before). Within 12 hours, it was 75% back to clear, by 24 hours it was crystal. It remains a little on the foamy side, by that is diminishing bit by bit.

I became the swimming guinea pig and all seems to be well.

Because, however, there are warnings about mixing OxyClean and chorine-containing products, I remain a little fearful of re-chlorinating the pool. Does anyone has experience with that follow-up step?

Q. Finding this forum gives me hope! - My husband "told me so" about buying an intex pool and filling it with well water... well water? How about "hell water" - fortunately as soon as I saw the pool filled with dark chocolate brown water I hopped online and found this forum.

The "filter out the iron -rather than douse it with chemicals" idea makes the most sense to me - I tried the towel trick last night and this morning was thrilled with how much iron it collected - though no visible signs of improvement in the water yet - I feel good about approaching the problem this way. I also found my old pump from an ornamental pond and put that on the third step of the ladder and filled the filter housing that came with the pump with fiberfill (another tip on this website)- and weighted it so that it sits on the pool bottom - I'm thinking this might work like the milk jug idea? - Here's a question for all of you - what about "faking" out the pump that came with the pool and using something to filter in the pump housing OTHER THAN the filter that comes with it? Any ideas?

I am glad I ran across this forum also. I have a 18x52" intex with the salt water system. My water was BROWN!I too was freaked out about using iron out. I did use about 2 TB to clean out my pump/filter and hoses. It worked great. But I could not add more to my pool for fear of hurting my children's skin. I went to the pool store, added an agent to remove the iron and used the sock over the out flow valve. I am shocked that in 2 days I have almost clear water, and after vacuuming and cleaning the walls- By tomorrow I WILL have nice inviting water! My kids can continue to swim in it while the agent is in the pool. One more word of advice~ by some extra filters from the pool store and you will be soo happy in 3 days! Good luck.

A. I made my own filter. I cut the paper off my filter. I drilled 4 1/16th holes in the blue rubber top and 4 holes in the same place in the top and bottom of the plastic center of the filter. I reattached the blue top to the center part with steel wire. Then I wrapped the center of the filter with a white towel, 4 layers thick. then I put 3 rubber bands top, middle and bottom to hold the towel on.
Change it every 3 hours if your pool is really bad. You can clean the towels with iron out, but rinse it thoroughly before reusing. I also used 3 bar-mop towels from wal-mart, fold them in half, sew 2 of the open sides together so it makes a long tube and attach this to the outlet inside the pool, change twice daily. my pool was thick and brown and after 3 days is now clear.

Q. I've a question. I have read all of the posts and love the idea featuring the gallon jug stuffed with fluff...but I am not clear on where to connect it. Please clear up my confusion! Thanks! Mia

A. We bought a intex 10 x 30 easy set up pool.We live in an area where there is only well water.We started to fill the pool, added chlorine, and it turned a dark brown. So we took some of the suggestions before we took down the pool and put Iron Out ⇦this on eBay or Amazon (affil link)] in the pool and it is completely clear. I also put a sock over the water pumping out to gather anything extra that the filter is not catching. I was worried about trying it but it does work.

A. I also have well water and asked a neighbor before I started filling my grandson's Intex pool and she was a God send . because her hubby made a filtering system for their above ground pool , when they have to add water , and all you have to do is to think about the system you have for your home, and buy one of those's cartridge systems ( just the container that the filter goes into, and then you buy a cheap hose and clamp one side to one end and the same to the other , then attach your outside hose to one end and start filling your pool and check a couple of times during the filling process to see if the filter needs to be changed. go to your local pool store and purchase mineral out , and not to forget when filtering the pool use the white sock over your old filter and run pool for at least 12 hours and check after the sock and change if needed , and your ready to go , I seems like a lot but buying the filter for 20.00 and filter the water while filling the pool believe me after shocking it you won't have 99% of the problems that most of you all are having.

A. I have a 24 ft x 52" pool that was set up two weeks ago. I used "mineral out" by HTH after filling (we have well water) and waited three days before turning on our salt water chlorinator. The pool was beautiful, clear water no cloudiness at all, thought I had conquered the iron. Oops it was only sequestered! We just had a major rain today and for some reason it cause the iron to oxidize and become visible. Water turned that wonderful brown within an hour after the rain. don't know why... Well I am going to remove the iron now instead of sequestering it. I will use the milk jugs tomorrow morning and let you know how it goes. Just know if you use a sequestering agent, if something changes in your water chemistry you could still have to deal with brown water.

I have had our 18' Intex pool set up for a month now and we are having the same problems as everyone in this forum. With the short swimming season here in Wisconsin my kids have been cheated by this bad water problem...we had the same water last year with absolutely no issues at all (make you wonder about what happened to the city wells).

At any rate I am thankful for everyone's solution, we are going to try the towel/sock method. We took the sample to on of the local pool "experts" and they gave me a bottle of acid that didn't appear to do anything (I believe it helped solidify the metal so the filter could remove it). We have been filtering non-stop for 2 weeks and instead of looking like 6,000 gallons of Coca-Cola we now have a lovely shade of Iced Tea. I hope the towel works...

I did speak to someone recently that mentioned Intex supplies the lowest level cartridge filters/pumps and they are woefully inadequate for the amount of water.

We went out and purchased a 4,000 Gallon Per Hour pump and we will see if that helps speed up the cleaning process.

Thanks for all of the advice and suggestions in this forum...I will update when we have results, good or bad.

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