Need to get piss clean?

Decided to go into the marines quit smokin weed the day i decided(bout 3 weeks ago).b4 that i smoked alot of weed everyday..been drinkin water pissing alot and my piss wont come clean..bought some "Strip" detox hoping that will work but any one have any more ideas it would help me out cuz the marines wanna enlist me ina couple days which means the piss test..so yea thx