Reversing Copper Corrosion

[fourcornersmark]

I let my pool pH get too low and am dealing with the fallout. We've had green hair, green in the filter, rust/metal precipitation in my liquidator when i dump the liquid chlorine in, etc. I only just noticed that at least part of my piping going back to the pool is copper, so it's clear copper corrosion started when the pH got low. Here's what i'm trying to figure out:

1. if i raise and keep my pH at appropriate levels will the corrosion stop?
2. how do i get my copper down to appropriate levels?
3. has anyone ever tried epoxy coating your copper lines to prolong their life rather than digging up and replacing with pvc (all my piping is under a concrete pool deck)?
4. does low pH have any other weird effects? i'm fighting a suction side air leak, sometimes the water fills to the top of clear lid and sometimes the water level drops to the pipe. i'm wondering if the low pH could have damaged my O-ring, or warped my lid or pump casing, or eats through the pool lube. I've already replaced the lid o-ring once this spring, and i re-did every accessible joint. i also tested pressure in the line and it holds, so i'm really just wondering it could somehow be related to the low pH (it was like 6.5 or something for who knows how long).

 

[JoyfulNoise]

If you keep the pool water pH tightly controlled between 7.5-8.0, then copper will not corrode. But it also sounds like your pool has serious issues.

How are you chlorinating your pool? Please post pictures of your equipment pad and fill out a signature … it’s hard to help without any info.

Copper can only be gotten rid of via fresh water exchange. A pricey consequence of living in CA.

Does your pool have copper stains? They’ll look brownish colored and then they will turn black if you apply vitamin C (as anscorbic acid) to them. If they disappear with ascorbic acid application, then they are iron stains.

Sorry, your only option to keep this from happening again is to get rid of all the copper piping. It’s annoying but old pools were built on the premise that copper pipes are best (well, better than cast iron) and at one point copper was cheap so it made good economic sense. Problem is that nowadays copper pipes are really bad for pools given the wide spread use of acidic chlorinating agents and newer technologies like SWGs. PVC is the only way to go for pool building these days.

 

[JoyfulNoise]

Also, please post test results … we really can’t give any specific advice without them. And don’t go to a pool store, their testing is worthless and you should always invest no your own test kit.

 

[Rocket J Squirrel]

I wonder whether your pool is about the same age as mine (1988). If so, there may be some good news. My original above-ground plumbing at my pad was copper, which eventually leaked and was replaced by PVC. The good news part is that all the underground pipes were and are PVC. Apparently, back in the '80s, they incorrectly thought copper was more durable than PVC when exposed to sun.

If you can dig down a little, maybe you'll find the copper is joined to PVC as mine was and you'll not have to replace all the pipes.

And I agree with what @JoyfulNoise said above.

 

[Newdude]

I let my pool pH get too low

How low ? While possible, it's suspicious to me that after all this time, you went 0 to 60 out of the blue.

Have you been adding copper with algecides, Xtra blue shock, (anything 'blue' for that matter), or an ionizer ?

 

[fourcornersmark]

i updated my signature with my basic info. my pH is now about 7.2, FC 2.0, alkalinity 70. i had been using a floater with 3" pucks while my liquidator was out of service (needed a new valve). those probably dropped my pH and i think i added some muriatic on a whim without checking the pH level and that's probably when it dropped into the 6's. after visiting the pool store i was told my copper was 3.5 so i drained about 15" and refilled (rough estimate 3500 gallons).

 

[JoyfulNoise]

Your copper levels are excessively high. 3.5ppm copper is about ten times higher than what would be necessary to see copper scaling, green hair, etc. You need to be very careful with pH so as to avoid copper staining.

And you really need to do your own regular water testing. The pool store is just not adequate for proper care.

You need either a Taylor K-2006 kit or a Tftestkits TF-100 kit so you can manage the water chemistry. You need to regularly test your water and keep your saturation index as close to zero as possible, even a slightly positive value. That will reduce the chances of corrosion. You also need to get rid of that pool water and refill. Since it’s a fiberglass pool, draining completely is too dangerous and so you need to do an exchange drain.

Draining - Further Reading

www.troublefreepool.com