I've never really been a fan of Si use in soils. It did some things for me in hydro but, nothing like what the makers can claim for their high priced products......I mean, tell people it will do XY&Z and by god they'll "see" almost exactly what makers "claim" in the first run with it....It's mostly confirmation bias at that point. In Coco? Are you having problems that would be helped by it's use? Go with your answer to that question.... See what I mean.