This entire post bothers me. Water filtration removes MORE THC than it removes tar. So you need more herb for the same high, and you inhale more tar for the same high. 

In a study of unfiltered joints, joints, pipes and bongs, an unfiltered joint has the lowest tar to THC levels. Of couse an herb vaporizer with a short airpath would be the best, as vaporizers have an order of magnitude less tar than any combustion smoking. Of course edibles also skirt this issue.