Has anyone tried coating the tippet with PVA to make it sink? Tippets don't sink because of the water surface tension, even though both nylon and fluorocarbon are more dense than water. A wetting agent should break the surface tension and detergent in the 'mud' does that, but it dissolves away too quickly. PVA is a wetting agent and so should break the surface tension. It is water soluble but hopefully would stay on longer than detergent, and possibly its polymeric nature may keep it on the line longer (??). It is non toxic to fish and used by carp anglers as PVA bags. I tried a little bit on some reflo powerline in the sink, just wiping the surface with ordinary PVA school glue. Without treatment it floated and initially it still floated after treatment. However, I pushed it under the surface and it sank like a stone. I then pulled it out and put it back - it immediately sank and kept sinking even after 5 goes. I think I'll take some with me next time I go fishing, wipe the tippet and false cast a couple of times to dry it, then see what happens.