Hey man i hear your problem and I use this everytime!!!!

first dilute the sample to buy you a couple days, then ASAP you need to get some creatine supplements. Take em everyday to make sure that you have abnormally high levels of creatinine(whats left after your body uses the creatine) in your sample. Morning of the test drink water till you get sick and unload your bladder a few times till your pissing water. 3-4 hours before the test take some b-12 or another vitamin to color your piss.

The only reason you cant really just color some faucet water is because the first thing they check for is creatinine to make sure you didnt load up on water but youll have taken care of this buy compensating for the extra water with extra creatinine. Good luck bro

NEVER USE BLEACH OR ANYHTING HARMFUL!