Is copper pipe OK?

[Water_man]

I wonder how stable copper is in pool water.
I have an old pool with two returns which are nothing but
unthreaded pipe holes of 13/16" ID.
I want to install eyeball jet returns for directing the flow in order to maximize circulation and I found a copper pipe that fits inside the hole. From there on I can build it up with a couple of PVC adapters where I can fit the standard eyeballs which are designed for 1 1/2" PVC.
I wonder how stable copper is in FC levels between 4 and 20. Is copper commonly used in pool equipment?

[waterbear]

Not these days. Even heat exchagers in heaters are going to copper/nickel and titanium alloys.

[Water_man]

Not these days. Even heat exchagers in heaters are going to copper/nickel and titanium alloys.

Does that mean that copper is a bad choice because it will leach out?

[chem geek]

Basically, yes. Copper will corrode (oxidize) becoming copper ions in water that can eventually stain. How fast this occurs depends on a variety of factors. The pH is most important with low pH rapidly increasing corrosion. Higher chlorine levels is another factor with the FC/CYA ratio being most relevant (or FC alone, if CYA is near zero). The conductivity of the water, roughly approximated by TDS or salt level, is another factor.

So a particularly corrosive scenario would be a pool without CYA (such as most indoor pools) with an SWG system (so the water has 3000 ppm salt) operating at a lower pH. Nevertheless, it would be best to avoid the use of pure copper in pools.

Copper pipes in homes have been exposed to chlorine (up to 1 ppm FC) with no CYA and have generally not corroded, but there is little dissolved oxygen in the pipes, there is little conductivity since the TDS is low, and there are some corrosion inhibitors usually added to the water.

Richard

[Poconos]

Richard,
Are you saying that public water companies add or may add corrosion inhibitors to their systems or are you referring to the sacrificial elements used in some water heaters?
Al

[chem geek]

Public water companies add corrosion inhibitors. When many of them switched to using monochloramine instead of chlorine, they had to switch to use different corrosion inhibitors. Initially there were reports of corrosion after the switch in some communities until they sorted this all out.

The sacrificial anode in water heaters is separate and is there primarily to protect the water tank (which is usually glass lined, but there are voids where this is exposure to steel), not so much for the copper.

Richard

[Water_man]

Then I need to work with a PVC pipe, but its OD is about 1/32" too wide. What's the best way to decrease its OD other than filing or sanding it down? I'm talking about no more than 4" to 6" long pipe.

[Poconos]

WaterMan....Never tried to reduce the diameter of PVC pipe, only expand a little, but PVC will get pretty soft in boiling water. Off the wall but maybe you can figure some way to extrude it through some kind of die when it is soft.
Richard....just what we need in drinking water. Another possible carcinogen. Any idea what these inhibitors are? I'll stick to my well.
Al