Advice on using pH Neutralizer and/or Softener for Iron filtration

Discussion in 'Water Softener Forum, problems, installation and r' started by gojoe3, Jun 3, 2013.

  1. gojoe3

    gojoe3 New Member

    Messages:
    68
    I am trying to decide whether to use my pH neutralizer predominantly for pH adjustment or for maximum Iron removal also. And whether my Softener can assist with iron removal if needed.

    My 9x54 pH neutralizer is now setup with a mixed media bed consisting of a 40 lb. gravel base, 1.0 cu. ft. of Birm, 0.50 cu. ft. of Filter Ag, and an unknown amount of Calcite. It seems to be doing a decent job removing the iron, but lacks the pH neutralizing qualities I need. Green staining appears on fixtures within 6 months of adding Calcite.

    Currently, the raw water pH is 6.4 and post neutralizer (kitchen faucet) it is at 6.5.

    I have some Iron, the amount varies. Last year's laboratory water test showed 0.19 mg/L . My recent personal testing results, using my Hach kit, shows aprox. 0.075 mg/L at raw water and ND (none detected) post conditioning.

    I would appreciate any advice on the options I am considering.

    One option is to use my current pH neutralizer tank with a mixed media bed (TBD) and to purchase and install a new air injector valve, like the Clack or the Fleck AIO. This would allow me to oxidize the Iron, filter it out, raise the pH, and get rid of the existing air injector which will eventually ruin my new pressure tank. Will I be able to remove the existing contact/retention tank, or is it better to use it as an off-air tank? Should I replace my 9x54 tank with a larger one so that I can add more Calcite and have room for the air space? Or just change the mixed media bed to better address the pH?

    Another option (which I would prefer), is to rebuild and use my existing, malfunctioning, Fleck 5600 12-day valve on the pH neutralizer tank with a new bed of only Calcite? Calcite/Corosex blend? This would seem to allow longer periods of proper pH adjustment because of the volume of Calcite compared to just the small amount which is added in the mixed media bed now. Will Ferrous Iron or Ferric Iron will be filtered by the Calcite bed?

    Will my 1.0 cu. ft. softener and its media remove any remaining Ferrous Iron or Ferric Iron that the pH media doesn't, without fouling it? Should I change the resin to a more iron tolerant one?Will a more frequent backwashing regimen be required because of the higher Iron content water which the softener may be subjected to. My current Hardness is 9 gpg/153.9 mg/L.
  2. mialynette2003

    mialynette2003 Member

    Messages:
    729
    Location:
    Ocala, Florida
    A 9X54 tank would be very odd. Could it be a 10x54 which is common? What is you water usage like? What is the .19 iron ferric or ferrous? Ferric iron of .19 is very little vs ferrous. I would suggest getting the ph up first before trying to remove the iron. Rebuilding your 5600 would be minor cost and last quite awhile. I think calcite/corosex would be fine. I have used it in the past.

    How old is the resin? What type of valve does it have? Softeners will not remove ferrous iron. If you are dealing with .19 ferric iron, use a softener and be done.
  3. gojoe3

    gojoe3 New Member

    Messages:
    68
    Thanks for the reply mialynette2003,

    I'm glad you think I could rebuild my Fleck 5600 valve and go the Calcite instead of mixed media route. How much Calcite would you suggest? I was considering filling the 9x54 tank to leave 1/3 of it empty for freeboard. How would I calculate the cubic footage of Calcite needed to fill 36" of a 9x54 tank? How do I determine if my Fleck 5600 pH neutralizer valve is setup to do downflow or upflow?

    My color tested out at 5 CU and the turbidity was 1.9 NTU. Will these be affected by the Calcite?

    I realize that 9x54 is an odd size but that's what it measures. It came with the original system that I purchased in 2003?. I used to use a Calcite/Corosex blend, but the new company I hired to maintain my system changed it to the mixed media blend in 2005, when they installed the Clack air injector.

    I would guess that my wife and I use an average of 100 GPD. The Fleck 7000 on the softener is scheduled to regenerate at 920? gallons and it does this every 8 to 10 days. The resin is now 8 years old. It may be time to switch to a more iron friendly resin, like SST-60.

    I do not know which portion of the iron is ferrous and which is ferric. The lab tests have only stated that there is 0.19 mg/L of iron, but not which type.
    I assume that I have both types. My Hach test kit is for Ferric. I tested raw water last week at around 0.075 mg/L. Does that mean that the balance of 0.115 mg/L is ferrous? I have a Clack U1020 air injector prior to my pressure tank. I test my raw water at the pressure tank drain valve. The water would be oxidized at this point and may have been mostly ferrous but may now be partially ferric after oxidation and precipitation.

    How can I test for ferrous versus ferric iron?
    From what you are stating this seems to be very important for me to determine before choosing an appropriate filtration method.

    I read that the Calcite or Calcite/Corosex blend would filter out about 1/3 of both the ferrous and ferric iron content.
    I think I was recently told that the ferrous iron would be filtered out by the softener resin. It was probably the other way around?
    Please confirm that softeners will not remove ferrous iron.

    Informative article I just found on iron filtration http://www.hillwater.com/resources/iron-removal.aspx
  4. mialynette2003

    mialynette2003 Member

    Messages:
    729
    Location:
    Ocala, Florida
    In over 23+ year of being in water treatment, you would think I would get the classes of iron correct. I always referred to them as clear water and red water iron. The name tells me which is oxidezed or not. Ferrous iron can be removed by water softeners and ferric is removed by another filter system. I use chlorination to oxidize the iron followed by carbon to remove it.

    I would not think of using a pH media to remove iron. The calcite and/or corosex media dissolves in the water adding the media to the water which will raise the pH as well as the hardness of the water. It may trap the ferric iron, but I would think that ferrous iron pass through it.
  5. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    It takes 25 years to get it right :). If you see red iron, think of your wife saying "ICK" -- i.e., ferrIC.
  6. mialynette2003

    mialynette2003 Member

    Messages:
    729
    Location:
    Ocala, Florida
    LOL Come on 2015.
  7. gojoe3

    gojoe3 New Member

    Messages:
    68
    Thanks for confirming that the ferrous iron can be removed by a softener. As I recall reading, most softeners can handle up to 3 ppm (aka mg/L). So, I suspect I should be ok in letting my softener handle the ferrous iron load. My iron tested at 0.19 mg/L for total iron. I don't know what portion of it is ferrous versus ferric. I also realize that ferric iron can foul the softener resin, so it is important to try to remove as much of the ferric iron as you can, prior to the softener and to setup the softener properly so that it can handle the iron load. To keep the resin clean I will continue to add Iron Out to my brine tank when I add salt.

    After researching the alternatives, speaking with local water conditioning professionals, and your input here, I have decided to rebuild my Fleck valve and rebed my pH neutralizer using only Calcite to replace the Birm/filter Ag/Calcite blend. There just wasn't enough Calcite in the mix to maintain a proper pH for a substantial amount of time. Besides raising the pH to a proper level, it seems that the Calcite will generally remove about 1/3 of the ferric and ferrous iron. I thought about upgrading to a larger tank with a dome hole for easier addition of Calcite, but one local guy suggested that removing the valve may be necessary anyway, so that I can siphon off the top portion of Calcite, which may become fouled from trapping some of the iron.

    So for now that's the plan. Will update soon.
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