Supplements to pass test...

I have heard from many people that there are supplements at GNC stores that can dilute your urine for up to 6 hours if taken 1 hour before a drug test. In the past, I also read about these types of products on this site for passing tests, but I do not want to waste money and get duped into buying faulty products if these are bogus. Does anyone know of anything like this that works so I dont have to drink a gallon of water or spend a ton of money on one detox drink. If i only buy one detox drink it wouldnt help me for tests in following weeks...