Acid-neutralizer or chemical injection?


  #1  
Old 06-17-08, 09:55 PM
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Acid-neutralizer or chemical injection?

My well water is extremely acidic: ph level = 5.5. I have copper piping in the house and I get that telltale bluish green color in sinks/tub, which, as I understand, is the copper leaching out of the pipes. I would like to keep the fix simple and use a single tank acid-neutralizer, probably with the automatic backwash feature. I already have a floor drain and GFCI outlets in the basement corner with my pressure tank, which is where I would collocate the acid-neutralizer.

But what I think Iím finding out is that:

(1) a ph= 5.5 may be far too low for an acid-neutralizer to correct
(2) many of these acid-neutralizers severely lower water pressure

Because of the above I was planning to install a chemical-injection system instead. My understanding is that they definitely can raise even an extremely low ph to the proper level. But I understand that you also need a retention-tank (in addition to and after the normal pressure-tank) to allow the injected chemical to mix and properly do itsí job. Iím not adverse to adding a retention tank also , but I think the final total required setup:

(a) chemical-pump on chemical tank, (b) electrical outlet that turns on/off with well-pump (to turn on/off chemical-pump), and (c) retention tank -

is obviously much more complex than a single tank acid neutralizer.

Iíve actually already added an electrical outlet that gets energy only while the well-pump runs Ė so it could be used to turn on-off the chemical-pump (if I ever buy one). But Iím having second thoughts and would like to keep the fix simpler if I could and not so quickly dismiss an acid-neutralizer as out of hand.

Anyone have experience with acid-neutralizers? Does anyone happen to know how limited they are in the amount they can raise ph? Do they really cause severe pressure drops? Are they a pain-in-the-butt to maintain?

Any thoughts would be greatly appreciated!
 
  #2  
Old 06-18-08, 05:37 AM
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Can you tell us other water test results? Hardness, iron, TDS?

Ideally, you want to achieve a level of 7.2 - 7.8 pH for residential use. Slightly lower than that or a little above is within acceptability.

Mineral neutralizers using Calcite alone are very effective from 6.4 and above. I usually use a mix of Calcite and MagOxide from 6.0 and up. Below 6.0 mineral neutralizers have a decreasing effect until practically no change occurs.

Mineral tanks also need contact time. IOW, the water must pass through the media slowly, or there must be a lot of media to allow actual contact time during heavy water use.

Mineral tanks come in two basic approaches. There are backwashing tanks that are placed after the pressure tank and before a softener, or an upflow tank sometimes placed before the pressure tank.

The backwashing tanks will reduce pressure to the house to a degree but unless you already have very low pressure or massive amounts of water use at given times, this is not typically a problem considering the damage acidic water will do to your plumbing and appliances.

Upflow tanks need high flow rates to keep the bed form 'cementing' and channeling. Placing them before the pressure tank assures against both.

Once water's pH is neutralized the minerals stop there work and won't dissolve any more. They reach a maximum pH and then stop; no worries about causing your water to become caustic.

Mineral tanks will also raise hardness levels slightly. Minerals are sacrificial and will need to be replenished and, at times, a 'dump-n-rebed' may be required. Large tanks (10x54) will be awkward but may be needed if contact time is required.

Chemical feeds using soda ash or sodium hydroxide can rapidly raise pH to just about any level depending on feed concentration, level of pH and other factors.

WARNING--Caution must be taken very much. I have seen systems put out levels of 12 or 13 pH due to improper set up, maintenance and design.

I do prefer retention tanks to blend water. Without them the solution is added to water only when the pump is running so portions of water will be either very acidic or neutral or basic. Retention tank will level to variations more adequately.

I also prefer peristaltic-type pumps as opposed to diaphragm pumps. More expensive but a bit easier to maintain and operate. Quieter, too. They click rather than thump.

Some people put the injection feed before the pressure tank letting it act as a mixing device before going into the retention tank. The solution will not damage the bladder as would bleach or other oxidizing chemicals. Hardness will not be affected with chemical feeds.

AGAIN, handling the chemicals must also require great care. Keep pets and kids away from stored chemicals and use gloves and goggles when handling. Avoid storing on shelves where they may fall or in locations where other objects may crash into them.

Did I answer your questions? Hope so. I can't understand contractors who build homes where acidic water is known and still use copper plumbing.

Andy Christensen, CWS-II
 

Last edited by AndyC; 06-18-08 at 05:50 AM. Reason: spelling
  #3  
Old 06-18-08, 11:25 AM
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Thank you very much AndyC for that great wealth of information and all your time.

Last iron reading was 1.72 mg/L . Manganese was 0.49 mg/L. I donít have a reading for TDS or calcium. These last results are several years old. But I just used strip testing and it tells me my water is still very acidic, so I believe the last reading of 5.5 for ph is still correct.

I was also wondering why they would use copper in a house where the water is so acidic? Itís 40 years old , but I would have thought that some other alternative piping would have been available at that time. I moved in 6 yrs. ago and found a bag of potassium carbonate on a shelf near the pressure-tank. I didnít understand what it would have been used for at that time Ė but now as Iím learning Iím thinking they either had or were very close to installing a chemical-injection system that used potassium carbonate ? I also found a tattered ďPulsitron Chemical-PumpĒ manual on the shelf, but a new electrical outlet half connected up to the pump motor control box ? So I canít figure out whether they were in the middle of installing or in the middle of de-installing a chemical injection system at that time? I guess thatís irrelevant now?

After digesting your information it seems to me Iíd be better off going the chemical-injection route. I think Iíll look for a peristaltic pump as you suggest. Sounds like the best pump. I did not know that. I was in fact planning to put the injection feed before the pressure tank. I was worried whether the solution would damage the tank (actually I think I have a diaphragm) but sounds like youíre saying not to worry. Good!

Looks like you also believe that a Retention Tank is a good idea. Very good! I was looking into an Amtrol Epoxy Coated Retention tank. From what I gather thatís a pretty good tank and I have plenty of room.

Unfortunately you confirmed something that does worry me (but thatís life). I donít like some of the inherent danger with a chemical-injection system Ė like causing way too high ph levels as you point out. No pets or kids to worry about, but who knows about someone else in the future.

I was thinking of using a more convenient and less expensive self-test kit (with paper strips) to make sure I stay in the ballpark with ph etc., but then periodically also getting a more accurate lab test.

Do you happen to know what a good testing frequency is for chemically treated a water? I was thinking of paper strips maybe monthly, but then a more thorough lab test every six months. Is that even anywhere in the ballpark?

I donít want to screw up the water with excess of anything and cause myself or anyone else to suffer a heart attack or something! (Maybe thatís nutty.)

Thanks again for all your time and information!
 
 

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