Green staining from softened water supplies

[johnb]

Obviously (?) there will be a small amount of chloride (from the regen. salt) left in the water coming out an ion-exchange softener. I've noticed a number of places where there are green stains on the bathroom, etc. fixtures, suggesting that copper is being attacked somewhere and deposited on the chinaware as (green!) copper chloride.

Is this an unavoidable / common problem with ion-exchange softeners?

Is it possibly because the water is being 'over-softened'?

best regards,
John
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best regards,
John

[Agile]

I have never heard of this before and expect its caused by a faulty softener.

The softener passes water over resin granules and these are rejuvenated by passing brine through them. After the brine solution the resin is washed in plain water.

The brine solution can be assumed to be saturated and providing its not excessively hot ( ? ) then I would question the wash flow and duration.

It is quite easy to measure the remaining brine content as this greatly increases the electrical conductivity. You can do a simple comparative test by placing your meter test probes about 15 mm apart and measuring the resistance of mains tap water which should be about 500k or above.

Next measure the resistance of the water at the output of the softener first immediately after regeneration and then just before the next regeneration.

If the resistance is much less that 50k then I would suspect the washing cycle. As I have never needed to do these tests perhaps someone else with a softener could do it and tell us the results as a comparisom.

Tony Glazier

Agile Services

[barbel]

Hi,

We have exactly this problem! I only realised when I discovered big wet patches on the lounge ceiling of the house we've just moved in to.

One of the pipes (which looked fairly new) in our bathroom had a tiny pin prick in it. On replacing it the pipe actually looked like it had corroded as the hole was surronunded by green staining. I've since noticed green staining round other joints.

Someone has suggested that an imbalance of chemicals in the water softener could be corroding the pipe work. Can this be?

Unfortunatley I'm no plumber of water softener expert...

Thanks,

Andy

[Agile]

All of you seem to be ignoring my advice that the softener seems to be faulty.

Part of the regeneration process is for the ion exchange resin to be immersed in salt solution and then washed with fresh water which is discharged to drain.

If this last stage is not adequately fullfilled then salt will get into the output and corrode copper pipes.

If the regeneration is carried out too often or with too much brine then the same effect will occur.

Get the softener checked by a professional such as the manufacturers service agent.

Tony

[barbel]

The service engineer has just left and after servicing the softener says that it's fine, other than having a slightly stiff brine valve.

He also said that the softener wouldn't have anything to do with the corrosion in the pipes....

Andy

[Hixxie]

"Green copper sulphate staining"
This is NOT caused by a faulty water softener.

It is normally related to either new pipe work where solder flux is used or in some cases Poor quality copper. There was a large amount from the Far East that was notorious for "pin holing" and staining.

With regards to having a softener in place...
This happens because there is no lime scale within the pipe forming a barrier between the water and the pipe itself. (Absorbed by the soft water)

This is not to say all people with softeners will suffer from this problem. Infact it is quite rare, but can happen depending on how aggressive your natural water is.

If you have some new pipe work fitted then the flux should clear over a short period of time. If you still find is doesn’t clear then fitting a tri-sodium polyphosphate kit will over come the problem by adding a protective layer within the pipes.

Hope this clears things up a little.

Regards James

[Agile]

Corrosion by flux would normally be copper chlorides rather than ( blue ) sulphate.

However that would be on the outside of the pipe as flux residues on the inside would be washed away pretty quickly on any supply pipe.

On a heating system any flux residues SHOULD have been flushed away when the system was installed but many cowboy fitters did not bother and the acids circulate and eat away at any weak points with impurities in the copper.

I expect any softener engineer is programmed to always say that their unit did not cause the problem to avoid claims! A stiff brine valve may have been introducing brine into the softened water somehow?

Tony



This message was edited by Agile on 5-30-06 @ 4:52 PM

[alanka]

Just for the record, I noticed the following paragraph in a User & Installer Handbook from 'Tapworks' water softener manufacturers:

"Copper Staining.
"In some cases small amounts of blue copper deposits may be noticed after installation. This will be caused by new pipework and should disappear after a short time. Simply wipe away any deposit. If this persists poor earthing may be allowing electrolytic corrosion. Contact an electrical engineer." (Why not a competent plumber?)

Cheers, Big Al
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Cheers, Big Al

[Hixxie]

A faulty brine valve (fleck) would cause the salt tank to overfill or no brine refill after regen.
And yes flux SHOULD be washed throu on a new system, but as we all know there are a lot of cowboys out there.

All Im trying to itterate is it is not nessasery to spend money on getting the softener serviced if you have blue/green staining. Better to look at the real reasons why this is happening.

PS.. I don't work for Tapworks either but well spotted Big Al.

[Agile]

But you did not notice that this discussion is FOUR years old!

[Chris]

(Agile years only have 4 months in them)

[Agile]

Time flies when you are enjoying yourself!