High iron - failing filox system

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by Muff, May 9, 2012.

  1. Muff

    Muff New Member

    Apr 27, 2012
    nothern wi
    Howdy out there.
    New place, new well, pissed off girlfriend and kid! My water has high iron and is hard. My first concern was getting the iron out and filox seemed the answer.Water seemed good for a month or two, but the iron ppm continues to rise post-filter(currently about 7ppm).
    When researching why filox fails I came across an ORP test (pot./perm. solution) that can be done without an ORP meter.Wish I'd known about this test before I bought my system because my water really fails the test.
    The well - 128', 5" pvc casing , 22' static level, flowed 22gpm, water temp. mid 40,s F. It was sized to service two homes.
    The pump - Grundfos constant pressure 15gpm(max.) set at 60psi.
    The water - The raw water has a light yellow tint and and is slightly stinky.When sitting overnight it turns a lovely shade of orange and develops a rainbow sheen on the surface(iron bacteria?)
    I had a water test done by NTL.
    Calcium ----------------50.2 All in mg/L
    Hardness---------------170 (9.9 grains)
    Sulfur - none detected by one of those glass tube home tests
    pH - 6.5 by NTL 6.8-7 by others on site
    The system I installed.
    Starts with a 4.5"X20" 5 micron prefilter to a check valve to a inline mixing valve to a 10"X54" air treatment tank (AerMax) to a 10"X54"1.5 cu.ft. Filox iron filter. The filter has a Fleck 2510 control. It was set up to backflush for 12 min. and rinse for 8 min.
    I also installed a Stenner adj. injection pump to inject bleach ahead of the air tank during regeneration(aprx. 4ppm). This was suggested to refresh the media bed and control nasty growth.
    I,ve spent hours researching (thats how I found you folks) how to fix this but there seems to be alot of Catch 22s with high iron water treatment.I,m tired of talking to salesmen sitting at a desk!
    Any ideas on how to modify/change/upgrade this system would be much appreciated.
  2. drick

    drick In the Trades

    May 16, 2008

    Your iron is no worse than mine and I have clear water. My setup is also very similar to yours. You are missing a critical component though, you need to insert a 100 gallon retention tank between the Air-Max/Chlorine feed and you filox filter. You are doing the right things by injecting air and chlorine, BUT it takes 20 minutes of contact time between the chlorine/injected air and the water before the dissolved iron turns to a solid. The filox filter cannot remove dissolved iron, it just passes right through the filter. You need the 100 gallon tank to give you that 20 minutes of contact time. When you install the retention tank add a valve so you can manually drain the bottom 10 gallons of the tank every week. The worst of the iron will settle to the bottom and by removing it before it gets to the filters helps.

    A few other things:
    -Your filox filter should be set to backwash EVERY DAY. If it has not been set to regenerate every day the filox media is likely ruined and will need to be replaced. I have mine set to backwash for 10 minutes and rinse for 2 minutes every day. Long rinse times will just add iron back into the tank you just backwashed so I do the minimum. It has been running with these settings for 4 years now with no media changes.

    -I would also remove the cartridge filter and move it to the end of your filtering process (if you use it at all). The filter reduces the flow rate to the filox filter during backwash and filox needs 9gpm. You should manually backwash your filox filter and use a 5 gallon bucket to measure the output from the filter. It needs to be 9gpm. If you end up replacing the media consider buying a vortex tank to replace you current tank. Vortex tanks supposedly help to fluff up heavy media more evenly during backwash to help prevent channeling in the media.

    -Also consider adding a 1.5 cu ft backwashing centaur carbon filter after the filox filter. The carbon will remove any residual chlorine and will remove the smell from the water. The carbon filter can also remove small amounts of iron that get past the filox filter. I have both a carbon a a filox filter.

    - I'm not sure if you have IRB or not. I had the same oily sheen you are taking about and it went away when I got the filters working properly. My well has always tested negative for IRB. But, if you do have it the chlorine should kill it as long as you are injecting enough.

    10ppm iron is a pain but filox is probably the best media choice to filter it out (IMO) and it will filter it successfully once you setup is correct.

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  4. Muff

    Muff New Member

    Apr 27, 2012
    nothern wi
    A reply! thank you thank you

    Hey drick,
    Thanks much for the reply.If you don't mind, I'd like to pick your brain since you have a working system.

    Backwash- My filter is set to backwash every day and it flows at 11gpm during. I like the fact that you're keeping your backwash to a minimum to reduce adding more iron.Makes sense to me, but how did you come up with the correct time? Would I look at the discharge and stop the backwash when it starts to clear up?

    Chlorine amount- Is your chlorine ppm dosing the full ratio (1 to 1 for iron I think) or are you doing a partial having the filox remove some of the iron?I came up with a dosing of 13.6ppm (iron+mang.+1ppm residual) which seems like alot.

    Sounds like I'll need to get a pulsing flow meter to convert to continous injection regardless.

    Carbon filter- I agree I'll need one of these as long as hard water won't foul it.I can't seem to find any
    info. on this. Also, are you doing any thing post filters to remove THMs? This is my main concern with a chlorine system and from what I read, carbon will only reduce them somewhat.

    Locaton of my cartridge filter- I put it 1st to protect the equipment down-stream mainly for warranty reasons. I could move it between the filox filter and carbon filter to help remove some of the precipitated if that would increase the life on the carbon.Some of the filox systems out there require one post filter, mine did not. Any thoughts on this?

    Filox media- Have you ever heard of a way to 'test' the media ? This stuff isn't cheap and if it's already ruined, ouch! I did pull the control valve to take a peek and found the freeboard (I think that's the right term) decreased from 16" to 13". So either my filter is making filox and I'll be rich or I've got a lot of crap in it. I'm betting on the latter!

    Rentention tank- I'm tight on space. I'm trying to get more info. on Auto. Pure Waters 12'X60' mixing chamber one. Anyone out there using one of these? I thought I hit a thread on these but I can't find it again.

    The online store I bought my system from hasn't been overly helpfull. Alot of "not sure" "don't know" .They did suggest I "might try amending the pH" due to my manganese. Wish they would've suggested the ORP test that shows filox alone will not treat this water.

    Thanks - Muff
  5. drick

    drick In the Trades

    May 16, 2008
    Its not the backwash time you want to minimize, just the rinse time. I use 2 minutes as the rinse time as this is the shortest time interval I can select and still have a rinse cycle with my control head. I think you need enough rinse time to settle the media bed and to flush out anything left behind from the backwash but thats all.

    Filox cannot remove the iron unless it has been converted to a solid so you cannot reduce the 13.6ppm number unless you have something else oxidizing the iron - like air. I don't recall exactly what mine came out to be (I think it was close to yours and I recall thinking it was quite high) but I didn't use the full ratio because I am also injecting air which can probably handle converting the dissolved iron to a solid all on its own. I am currently injecting 5ppm chlorine along with a 10% solution of soda ash to bring up the PH a bit. However the real test is to see how much residual chlorine is present at the kitchen sink. Once your water is clear if the chlorine level is greater than 1ppm you can reduce the amount of chlorine you are using. If it is less than 0.2ppm you need to add more chlorine.

    I don't think that the hardness will have any negative effects on the carbon filter. Mine is between 50-100ppm after the filters. The carbon filter should reduce the amount of THMs in the water, however we do not drink our well water so I haven't put much thought into this. Our water tests ok for drinking and it tastes ok, but I do not trust that the well is free of near surface water contamination all the time therefore we don't drink it. If you are concerned about THMs you have the option of not injecting chlorine and just go with air injection system. One thing to remember is that a carbon filter will remove any residual chlorine so you have to check the residual chlorine either with the carbon filter bypassed or from a spigot you install between you filox and carbon filters.

    As long as you are getting 11GPM during backwash the pre filter is probably not harming anything. My only concern is if the pre filter starts to plug up and reduce your water pressure the filox filter may not have enough GPMs to backwash properly. As far as requiring a cartridge filter as a post filter after the filox I have never heard of that. I do have a cartridge filter housing after my 1.5 cu ft filters, but I leave it empty. I have it there for when I do media replacements. Sometimes the new media doesn't settle right away and pieces of it can be washed into your house piping. The post filter will prevent this.

    Or the media has been fluffed up a bit by backwashing. If you have been backwashing it daily I doubt it has been ruined. The only times I have read of filox failing has been in cases where the homeowner did not set the filter to backwash daily. Filox supposedly lasts almost forever as long as its backwashed every day. As far as checking the condition of the media the only way I know of is to dump it out and look at it. Failure to backwash it properly will result in the iron becoming permanently bonded to the filox.

    I think the lack of a retention tank is your real problem. I initially tried to get by without one and the treated water was only marginally better than the untreated water as far as the iron level was concerned. Adding the retention tank solved the problem instantly.

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