Backyard Aquaponics
A place to discuss aquaponics

I am not convinced that the copper will cause a problem. I will believe the copper testing I will do each month. If I see any, then I will do the galvanic thing with my 13 volts. Then if testing says that is not enough, it would be time to remove the copper. That would be a mess with 6" inside the concrete wall. I consider one inch pipe to be minimum for circulation, so slipping a plastic in the copper would not do. The OD of plastic is larger than the hole in the concrete...very messy indeed

If the large amount of copper in my system does not cause a problem, then many on this forum will have to take note of that. People have been using copper pipes, kettles, pots, and stills for a long time. Copper stills produced some excellant 'shine'. It was the lead in the car radiators that made some poisonous alcohol. Of course, enough 'squeeze' and you do not have to worry about the copper!

The heat exchanger uses an alcohol mix to circulate to the exchanger in the sun. The outside of the pipes are coated, so no copper/water contact.

Yup. Suck it and see. A good approach. Take one for the team! Empiricism has it's place.

Good luck with it. You may find as long as you have the high ph it will not be a problem. 6" of concrete is not a problem. You can get some nice core drill bits. Concrete drills are cheap also. If you don't like re-drilling a hole just make a new one and fill in the old ones.
Keep us posted.

found this link that gives some information on toxicity of metals.

http://www.fao.org/docrep/009/t1623e/T1623E03.htm

I am really interested in your research due to looking at hooking up a water heater to the system and they seem to all have copper heat exchangers.