Consider yourself lucky that you, a job applicant, was granted a retest by the employer. Theres many employers that simply move on to the next applicant for hire upon recieving a "diluted" test result from the lab MRO.

Lesson: When utilizing dilution techniques, its advisable to keep some validity test strips at hand so you can stay on top of your S/G and creatinine levels. Creatinine and S/G are tested in determining an overly-diluted sample. Creatinine and S/G checks have become SOP in recent years, making sample "color" the least aspect in determining a diluted sample. Even samples with a nice yellow color to them can still register unsatisfactory S/G and creatinine levels.

Validity test kits are inexpensive and are found online by doing a Google search for "drug adulteration test kits". These kits can also be used to check the creatinine, S/G, pH, etc. in both human and synthetic subs.