Built a new house in 1990, using copper pipe in all water supply lines. But in the past several years had to do some repairs, (so far all the repairs have been near the water supply area). Small pin holes develope in the copper pipes.
Water supply is from a deep well, there is some sulfer in the water. A Culigan water softner & Culsorb (uses potassium to remove the sulfer) was added to the water system.
What is eating away at the copper pipe?

What can be done to eliminate the problem?

Seems like a leak develops durring the hollidays when stores are closed. That is why I keep extra pipe and fittings on hand at all times.