I tried out a new line I acquired, a Rio Mainstream Sink Tip. After about a half hour of experimentation I determined that the sink rate could be measured on a calendar. Weird. I tried casting it after I had thoroughly drowned the line (thinking maybe it needed to be soaked???) The floating section floated great. The "sink tip" sunk about 2 inches in 3-4 minutes with a weighted nymph and fluorocarbon tippet (heavier than water...). It just sat their just under the surface and laughed at me. Ohhhhh welll..... anyone had this problem before? I just returned the Mainstream and am looking for a decent WF6/S3 as the Mainstream really sucked canal water. Argh.