FYI,,,We ran into the guy that makes it as he was trying to get stores/marinas to sell it in the Ticaboo area a year ago. He told us about it and the testing they had done with good results and that it was approved for use. So we bought some from him and applied it just before launching Cals Houseboat, ( we did not have time to cover all areas as we got it just before scheduled put in) We put it along the weld seams on both pontoons ( those were areas that had high muscle counts noticed on previous pullouts) and around the outboard motor water intakes. You could see it was still on the pontoons and motors after being in the water from April until we pulled it out at the end of October. It appeared there were less mussels attached in those areas we applied it, but it was not completely clear of them.
We think it did make a difference, but mussels seemed to be less in untreated areas as well. I think it is worth using at this point, we plan to reapply it in more areas before launching this spring. The active ingredient is Capsaicin. We had read before that it has been proven to be a deterrent to muscles and barnacles. This manufacturer is the first to get it approved and figure out a way to effectively apply it.