Several other shocking pictures were found down there including the whole crawl space was covered in white dust which looked like Boric Acid. 

Or they added that section later.Concrete is fairly inert once dry, so I would suspect thin wall copper combined with acidic water supply = pinholes.

Muratic acid should not damage drain plumbing.

I put boric acid down a couple of times throughout the house, some of them crawled out into the open and died, and that was that.

Stock brokers use the acid test-quick ratios, earnings per share and ratios based on a snapshot in time of an investment.

The inspector said it had a higher gloss which would make acid etching difficult so I'm trying to decide if I should just try and seal it with some sort of paint/sealant, and then carpet.

I do not recall ever having an issue with clay tile and an acidic drain cleaner. 

@Brent Paul The battery pack is completely different chemistry than a lead acid battery.

It’s an art, not a science so I can’t get into all the details here in one post, but I can guarantee that by the end of my three day course you will be able to tell within 4 minutes and 20 seconds whether your applicant is on the swag, the meth, the crank, the acid, the booze, the bath salts or the good stuff.

If there is no flowing water you could scrape, acid etch, and throw drylok on there for $100 in materials - easy DIY job.Note: you do have electric and plumbing there that need to be moved for proper sealing,  so you would want to have pros handle those pieces.