Because your current regime is a dilution technique gone completely out of control. For starters, drinking fluids days before the U/A is useless. It may make you urinate frequently, but it has no effect on the rate in which THCA is filtered from the bloodstream by the kidneys. Drinking fluids is only good for the day of the U/A.
Drinking gallons of fluids on the day of the U/A will increase the chances of the sample being deemed "overdiluted". For the proper way to dilute, follow the steps outlined in the Dilution sticky thread.

Detox drinks are a scam. Their makers and peddlers exist only to seperate the credulous from their hard-earned cash. You can spend upwards of $200 for a magic elixir and accomplish nothing different than you would accomplish with just vitamin B2 and water.

Forget the magic detox potions and drowning yourself with gallons of fluids and just follow the Dilution sticky thread.
Burnt Toast Reviewed by Burnt Toast on . Hey, LabCorp tomorrow. First off let me apologize if this has been posted somewhere already. (I searched and the threads/posts that I found were dated back to 2007-2008). I am 5' 10" 205 pounds. I have only been smoking for 3 months, but have averaged about 1 gram of high grade a day (Shared with a friend or two). I have been clean for 4 days. (Today is the 4th and tomorrow (day of test) will be the 5th) I have drank 2 gallons of water and 1 2Liter bottle of Cranberry Juice I have the '1 Step maximum Rating: 5