During field training, the Petro-tite determined there was a leak. We dug up the lines and found a pinhole leak at the first elbow going to first pump. My figures said losing about .222/gal per hour.   They had used 2” single-wall FG inside 3” single wall for secondary containment and it was leaking at the containment fitting possibly from over-prepping the pipe at installation. We have complete faith in our Petro-Tite tester. Needless to say, I probably won’t be using the company who initially passed the line.