Whole House Ferric Iron removal?

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JBMaine

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I have a new well, drilled last fall and put into service in February. I've had three water tests done. The first test was done when we were able to get the water in the well to "clear up". The water tested great, was mildly hard, no iron to speak of, no manganese, really just nothing in it. Fast forward a week and the majority of the time the water is cloudy/tan and will leave a light rust colored stain in the toilets that brushed away easily. The small cartridge filters that came with the house are stained rust colored. The second test showed elevated levels of iron and a mild rise in manganese, but everything else checked out okay. I had another test done to confirm what I was seeing and find out if it was ferric or ferrous iron.

The most reccent water test showed:
Iron .7 mg/L - They indicated that it was all ferric iron with no ferrous present. (No iron bacteria either)
Manganese .017 mg/L
PH 7.2
Hardness 4 GPG

At the same time they recommended a 1.5 cu/ft backwashing filter with Greensand Plus (clack setup).

My question is, why would they go with a greensand filter if I don't have any ferrous iron to remove? Shouldn't I be able to go with some type of carbon or other media backwashing filter followed by something like a 1 micron cartridge filter to clean up anything that sneaks past the media filter?

I'd really like to get something ordered soon to take the ferric iron out of the water but I'm not really sure what type of filter media to use. Thoughts?
 

Reach4

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Iron .7 mg/L - They indicated that it was all ferric iron with no ferrous present. (No iron bacteria either)
Could you have gotten that backwards? You don't often see a mg/l number for ferric.

There is better media now than Greensand.
 

JBMaine

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No, definitely ferric. Always visibly present in the water, not "clear-water" iron. Just looked at the test results again and they clearly say mg/L. The verbage in the proposal says they propose "a Repco 1.5 Cube Iron Filter to correct Ferric Iron and Sediment. This system includes a Clack digital WS automatic backwashing Filter Head and 1.5 cubic feet of filter Multi-Media."

The spec sheet they attached identifies it as greensand +.

My bigger question is, knowing that it's ferric, what type of whole house system would work best to remove it? I'm thinking it still needs to be a backwashing filter but don't know what type of media would be needed. I haven't heard back from the water treatment company since I asked why they would use greensand + for ferric removal.
 

ditttohead

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Katalox Light will remove ferrous and ferric iron in many applications without an oxidizer. KL is based on Clinotilolite and reduces sediment down to 3-5 micron in most applications. I prefer KL over GS+, but either one should work for you. Even though it is currently all Ferric, in the future ferrous is very common if the pH drops slightly. GS+ is typically used with a regenerant.

I say go with the KL. The Clinoptilolite (Micro-Z, Turbidex, Zeosorb, Nextsand and many other names) should work and is slightly cheaper but will be ineffective if the iron starts to come in a ferrous form.
 

Reach4

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I would follow that backwashing filter with a cartridge filter. I like the Pentek Big Blue 20x4.5 housings. They tank a wide variety of filters.

That size filter may or may not be overkill. A bigger cartridge will have less backpressure, longer life and maybe both. Don't use a cellulose filter, but most cartridges/elements are not cellulose anyway.

Alternatively, consider the 10x4.5. You can replace the sump (blue part) later if you wish you had gotten the bigger version.
 

JBMaine

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I did finally hear back from them today. The spec sheet they sent on the media was wrong. They aren't going to use greensand plus, but something they refer to simply as "multimedia" which I gather is a series of different types of media. I do plan to have a cartridge filter after the backwashing filter. I had a twin Big Blue 20" filter setup at the last house. Sediment followed by carbon, and really liked that setup.

I'm not sure I want to go with KL right now. There is a part of me that would like to go with a non-ferrous removing media, partly so that if it does change I'll know, and at that point, I'll re-test, evaluate, and change out the media to adjust as needed.

Thoughts on Chemsorb media? Seem like it would do the trick as well for what I need currently. Filters down to a small size, relatively light, lower backwash flow rate required and less wasteful.
 

ditttohead

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Simply Clinoptilolite and it has the same backwash requirements as KL. KL is manganese Dioxide coating/impregnation of Clinoptilolite.

I would not recommend a BB Carbon after the system. Not enough carbon to be effective and too costly to maintain compared to other carbon treatment methods.
 

JBMaine

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Probably should have clarified, I don't plan on the BB carbon in this instance. At the other house I had a mild Hydrogen Sulfide problem that the axial carbon filter was clearing up quite nicely. It will most likely be a single 20" cartridge after the filter. Thanks for the opinions, I appreciate it.
 

ditttohead

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A sediment filter after a properly designed and sized Clinoptilolite system is typically not needed. If you do install a filter after Clinop/tank treatment be sure to install a proper 3 valve bypass so when the BB leaks, breaks or has a problem you can bypass the filter.
 

Reach4

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It seems to me that if the sediment filter after the backwashing filter is not needed, the cartridge will last a long time. It would serve as a QC on the backwashing filter, and would catch the sub-5 micron stuff.

I would be thinking of using maybe something like the PENTEK-WP1BB20P in there, which I use as my last stage. Maybe there is a pleated filter in that class that would be even better.
 

ditttohead

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We use pleated, string wound and Melt Blown. For the majority of applications a melt blown filter is good. We sell the Pentek but our main seller is a USA made Melt Blown Filter.
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shane21

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I would also recommend the KL filter. This would give you flexibility to still handle the iron should a ferrous condition arise by adding a secondary oxidizer (liquid injection or air draw) if needed. If you want to go the greensand route I would recommend Clack's MTM greensand alternative. I used to be a big proponent of GS and GS+ but have had enough trouble over the years with them that I have switched to Clack MTM GS alternative. Bags of GS and GS+ started having too many "fines" in them, often times requiring 2-3 hrs of initial backwash to properly remove it and even then some of the fines remained. Those fines are murder on a GS or GS+ filter once they make to the distributor. I have not replaced one MTM filter yet due to premature distributor plugging.

If you want a post filter don't even waste your time with 1 micron and larger nominal sediment filters as a QC "safety net". When installing post-filters after oxidizing iron filters, as iron "safety nets", just use the .35 micron pleated cartridges. They are more expensive but your trade-off is a filter with a lot more surface area than the cheaper string wound and cellulose versions and thus high flow, low pressure loss. But the main reason to use a .35 micron cartridge is that it will catch any ferric iron slipping by your GS/KL filter if that is your concern. Spend the money on a properly sized GS/KL filter and your post filter cost should be a non-factor as it should only see iron in the rarest of occasions allowing you to stretch filter life to 6 or perhaps even 12 months.
 
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