Very interested in a SWG for my pool, but have been given mixed answers to this question: can a SWG be used with an older pool with metal (I guess copper) plumbing?

Pool is gunite/plaster, about 30 years old, 25K gallons. Replastered about 5 years ago. All equipment plumbing is PVC, but plumbing to/from pool appears to be copper.

Some say, "no problem" others say, "the salt will eat it up" What's the real answer??

Thanks!