FBR, Though what you say is quite true.

The tea I'm drinking have 72mg of antioxidants per240mL.

Which would lower the THC metobolite concentration. I thinkyou overestimate the amount of water I consume as well. I drink maybe 8 glasses in the whole week. The green tea is the major player here. I normally don't drink much water until I am within a week or two of a test.