Tankless heaters

[GHM]

but it looks like copper piping which is not great for chlorinated water. .

Well, Looks like I may have a problem then...
My pool is plumbed completely with 3" copper piping. So far it has been working fine for the last 60 years and I don't see any deteriation. Now that I think about it all my home water supply lines are copper and my municipal water has 2-3ppm chlorine added.

[cleancloths]

Copper might be fine for 1-2ppm cl2, but it sure is not good at 10-15+ ppm like when you shock the pool. With the price of copper today you should rip out all that piping and replace it with PVC and sell the copper on the open market. I went to Lowes today to get some copper pipe and it was more than double what I paid a year ago.

[GHM]

Copper might be fine for 1-2ppm cl2, but it sure is not good at 10-15+ ppm like when you shock the pool. With the price of copper today you should rip out all that piping and replace it with PVC and sell the copper on the open market. I went to Lowes today to get some copper pipe and it was more than double what I paid a year ago.

My pool has had "60 years" of heavy shocking and clorine abuse, along with harsh Canadian cold and hot climate, and I've never had a single leak or problem.
Agreed at todays price for copper, I could not afford to plumb a pool with it, but next to stainless steel, copper is the "BEST", most durable, longest lasting, material for pool plumbing that money can buy.
Ripping it out as you suggested is a rediculous option as I would then have to pay to replace a perfect deck and then install crappy plastic which deteriates and leaks. I'd rather leave it and enjoy the comfort of having a plumbing system that will outlive me!

[cleancloths]

Ripping it out was a joke! I was just trying to explain it was overkill at today's prices. Really though, metal is not the best piping in terms of chemical resistance. You are lucky that you have not had corrosion creating many pin holes over the years. I worked for a number of years in a chlorine production facility and we would never use copper for anything that had low concentration chlorine.