A one time high can take 5-7 days minimum, but with your body size it may take longer. If your going for a pre-employment drug screen then substitute and keep on toking. Take back the detox drink and buy yourself some Quick Fix, its 100% effective if you get the temperature right. If your uncomfortable with that then i would hold off for a couple weeks and exercise. Buy some test strips and test yourself, drinking lots of water is not going to get you clean.
Metamucil is a great source of fiber and will also help to rid you of thc metabolites. Read the dilution and substitution stickies above and do your research. There is alot of great info here that can help you.:thumbsup: