pH, softener, iron question

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diggity

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Hi - so I'm the guy who asked some questions about a treatment system for a high iron/high hardness, low pH system a few weeks ago. A recent water test is below - copied from my original post, BUT... with a more accurate pH measurement (long story, I have had several pH tests, one of which I didn't believe, but turned out to be right). Anyway, here are the measurements:

Coliform: 0
Sodium: 157 mg/L
Potassium: 6.45 mg/L
Copper: ND
Iron: 18 mg/L
Manganese: 5 mg/L
Magnesium: 39 mg/L
Calcium: 252 mg/L
Zinc: 0.16 mg/L
pH: 5.32
Turbidity: 200 NTU
TDS: 1,795 mg/L
Alkalinity: 20 mg/L
Chlorine: ND
Chloride: 426 mg/L
Hardness: 792 mg/L
Nitrate: 4 mg/L
Nitrite: ND
Ammonia: 10 mg/L
Sulfate: 534 mg/L

Current system:
Well -> acid neutralizer -> pressure tank -> sand filter -> softener

Right now we have a big softener, which is removing most (but not all) of the iron. A few weeks ago, I said I was in the process of replacing the calcite in the acid neutralizer, which I did. However, it has not changed the pH very much, according to my test strips. The pH after the neutralizer is maybe a quarter point higher than before, and that's it. I'm thinking that there's just too much acid for the calcite to neutralize and/or the flow rate may be too fast. Anyway, now I'm wondering if I should use a sodium carbonate injection system to moderate the pH, instead of the calcite? But I'm still confused about what the ideal pH would be for the softener, especially considering how much iron we have ... I don't want to foul the resin or reduce its efficiency. I read that softeners work better at a low pH, but iron removal occurs best at a high pH. So I'm scratching my head. Any advice is appreciated - thanks!
 

Reach4

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I suggest you do the following search: calcite corosex

Somebody will probably give you some good info, but some reading in advance will probably be useful.
 

diggity

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I suggest you do the following search: calcite corosex

Somebody will probably give you some good info, but some reading in advance will probably be useful.
Thank you, yes, I have read about Corosex, but wouldn't that make the job even harder for our already overworked softener? That's another reason I'm thinking about soda ash instead.
 

ditttohead

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Soda ash would be a good direction.

You should strongly consider a proper iron/manganese reduction system design. A softener is a very poor choice for iron/manganese reduction when it comes to environmental issues, excessive salt usage, etc.

Softening iron reduction works best at low pH, most other forms of iron reduction equipment work better at high pH. Lower pH and softening reduces the fouling of the media, but regardless, it is not a good solution to your water condition.

Calcite does an excellent job of neutralization, but contact time and water temperature are factors that must be considered. Very low water temperatures, high flow rates will not see satisfactory results with calcite. You could try blending in Magnesium Dioxide media into the calcium carbonate, this will allow for slightly higher flow rates, but if the Calcium carbonate is not working, you are probably flowing the water too fast through it.
 

_John_

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if you did the soda ash injection, you could rebed your neutralizer with carbon or Katalox Light. Though even then I'd suspect you would need a chlorine injection with contact tank to oxidize all that.

so: well-pressure tank-chlorine injection-contact tank-soda ash injection-activated carbon/KL filter-softener.

I say carbon/KL because if you inject enough to leave a residual, carbon would probably be the media of choice to remove the excess chlorine. I'd actually prefer a mix of both medias in a filter so you account for changes in chlorine strength as your bleach sits in the tank, as KL would be the better choice if any Fe or Mn were leftover after injection/contact.
 

diggity

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Thanks folks - so John, I never considered the possibility of rebedding the softener with KL and/or carbon. What about the hardness? Or would lowering the pH precipitate it all out as calcium and magnesium carbonate?
 

_John_

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Thanks folks - so John, I never considered the possibility of rebedding the softener with KL and/or carbon. What about the hardness? Or would lowering the pH precipitate it all out as calcium and magnesium carbonate?

I said add the soda ash injection and rebed your current neutralizer with KL/carbon. I'd keep the softener.

And you could also inject the soda ash just after the chlorine or before your pressure tank as well. Injecting as you pump water (so before the pressure tank) is probably the most consistent, but chlorine is actually a little more effective at lower pH.

There's a lot to consider with that water...
 
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diggity

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Oh sorry, I read it wrong. I was a bit sleep deprived yesterday.

Anyway, thanks for the info. You're right - there is a lot to consider with our horrible water (like whether to roll the dice and just drill another well... but we probably don't have the money for that gamble).

So coming around to the thing I've been wondering about in my previous thread... is there any sense at all to doing pH adjustment and iron oxidation AFTER softening? My thinking is thus: If the softener operates better at a low pH, then maybe it should be allowed to do so. It would also knock down the majority of the iron. After softening, then adjust the pH, then on to the oxidizing filter (KL). So the flow would look like this:

Well -> pressure tank -> softener -> sodium carbonate injection -> contact tank -> KL

Am I barking up the wrong tree? Thanks again.
 

Bannerman

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My thinking is thus: If the softener operates better at a low pH, then maybe it should be allowed to do so.
Softeners do not operate better at low pH. The issue is in removing iron build-up from the resin.

When a softener is exposed to iron, then additional ongoing maintenance is required as the iron can foul the resin, making it less effective at softening. Usual preventative maintenance involves regularly utilizing an acid cleaner during the brine cycle, to assist the brine in removing the iron deposits. As low pH water is already acidic, then the need for a separate acid cleaner maybe reduced or even eliminated.

Locating a softener before the other treatment devices, places the softener as the primary iron treatment device. While a softener may be effective at removing/reducing iron, it is inefficient at doing so and should not be its primary purpose as there are other methods which are more effective and efficient.

Your water has a high amount of iron, manganese and hardness. You require specialized treatment for those conditions. Softening is generally the final procedure to be performed.
 
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diggity

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OK, got it - thanks for the quick reply. So it sounds like I should put the softener last, and be sure to always use ResCare or Iron Out in the brine tank?
 

Bannerman

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and be sure to always use ResCare or Iron Out in the brine tank?
Once a proper iron/manganese reduction system is in place, that should reduce or eliminate the need for further acid cleaning of the softener's resin bed.

pH adjustment is generally performed prior to iron reduction as iron reduction most often requires a higher pH for best effectiveness.
 

metalgodz

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I'll piggy-back onto this, as I'm in the same location, and kind of the same situation, water-wise. If a mod wants to move to its own thread or would like me to do so, no problem here.

Bad manganese and iron staining, failed greensand setup.

Two tests I have formal records for:
Test; 2008 result; 2010 result

pH; 7.2; 6.68
Hardness; 69ppm; 72ppm
Iron; 1ppm; 3.77ppm
Manganese; .31ppm; .41ppm
Turbidity; 19NTU; 41.1NTU
Sodium; 10ppm; 7.70ppm
Chloride; 4.2ppm; 5.76ppm
Sulfate; 26ppm; 42ppm

I know that the pH swings very low during wetter times of the year, and those are the times that I've had the worst time with the existing filter (Kenmore filter, venturi cleaning required every 2-3 weeks, pot. perm. tank cleanout every 6 moths), and the times when the staining has gotten REALLY bad.

Local outfits (that primarily/only stock/sell softeners) have all recommended softeners. I have no good place to dump salty water, and I really don't want to be dumping salt water, anyway.

The last place I called has no incentive to sell me install services, and down-sold himself by giving me the recommendation to use the existing chemical feeder with his setup. System would be my existing carbon block for silt, etc., followed by his 1.0 CF calcite tank (upgrade to Vortech?), followed by a 1.0 CF solid manganese dioxide tank (air injection if I want it, backwashes with just water, or with water plus bleach using my existing chemical feeder).

Is this sound? Thoughts on the Vortech vs standard tank?
 

Reach4

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I'll piggy-back onto this, as I'm in the same location, and kind of the same situation, water-wise.
pH; 7.2; 6.68
Your pH is very very different from Diggity. You don't need calcite or any other pH treatment. Your iron is much less. You still would benefit from an iron filter. Do you smell hydrogen sulfide?
 

metalgodz

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Your pH is very very different from Diggity. You don't need calcite or any other pH treatment. Your iron is much less. You still would benefit from an iron filter. Do you smell hydrogen sulfide?
Still need to pick up some more strips, but the pH has been in low 6 range before, and staining coincides with the low pH periods.

Low pH and staining have always occurred follwing a lot of rain, and/or in the spring. According to the original owner and builder, well is 80' of casing and an additional 60' of bore into rock, but the pump sits only about 80' down. System pumps up 90' vertical to the pressure tank in the basement.

Hydrogen sulfide is minimal, but detectable when there was no carbon in the sediment filter (carbon impregnated paper or carbon block), before the iron filter was first installed.

The info I've read on the manganese dioxide media all says "pH from 5 to 9, variable," but all the recommendations I see from people selling it say that the capacity is reduced by mid-6, and the time to remove manganese increases to an ampunt of time that makes most systems ineffective when the pH is that low.

If helpful, I'll redact and upload the rest of the test results.
 

Reach4

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Low pH and staining have always occurred follwing a lot of rain, and/or in the spring. According to the original owner and builder, well is 80' of casing and an additional 60' of bore into rock, but the pump sits only about 80' down. System pumps up 90' vertical to the pressure tank in the basement.
This raises the question to me as to whether the well is properly sealed around the casing. This is not to say that there is a leak is for sure, but it makes me suspicious.

Does your casing extend a foot above ground as it should, or is it something else? If it is something else, I would have that extended despite it being expensive. I had my pit demolished and my casing extended. I am very glad I did.

Still need to pick up some more strips, but the pH has been in low 6 range before, and staining coincides with the low pH periods.
I like Hydrion (O67) Urine & Saliva pH Paper 5.5-8.0 instead of broad range test strips.
 

metalgodz

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This raises the question to me as to whether the well is properly sealed around the casing. This is not to say that there is a leak is for sure, but it makes me suspicious.

Does your casing extend a foot above ground as it should, or is it something else? If it is something else, I would have that extended despite it being expensive. I had my pit demolished and my casing extended. I am very glad I did.
Could it be a problem with it not being sealed further down? The casing used to extend a full foot out, but has gotten to more like 6-8" on one side as some driveway settling has occurred.

I like Hydrion (O67) Urine & Saliva pH Paper 5.5-8.0 instead of broad range test strips.
Thanks for the recommendation; I'll take a look for them. I've got an aquarium kit and a pool kit around somewhere, too. :)
 

Reach4

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6 inches above is enough if there is not a real flood. Some wells were made with the well seal in a pit or buried. There is still a worry about the grout job on your well I think. I wish there was an easy test for that. E coli detection would seem to be positive for that. Hach sells a Pathoscreen kit that lets you do pathogenic bacteria tests many times at home.

How much time delay is there after a big rain and when you detect a change in the water?

If you have narrow range pH strips made for an aquarium, they might be even better. The aquarium folks are usually pretty careful about getting pH right. I would avoid broad range strips. I read there are inexpensive pH meters. They need a calibration solution, but it seems that might be good for somebody making frequent pH measurements.
 
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metalgodz

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Total coliform for both tests ('08, '10) was zero / "absent". The well was about 10-11 years old at that point.

A couple of days of heavy rain will produce a noticeable change in staining over the next few weeks, but I can't tell you how soon afterward the pH changes - I just took measurements in response to noticeable changes. Overall, it's more a couple of months of the year that are particularly bad. March, April, May, September, October.

I'm only now realizing how much more thorough I should have been...Now that I've got a failed head/valve. (And now that I'm showering in raw water. Staining in 1 week of raw water = staining in 1 month of treated water.)
 
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