I connect my blow-off hose to the inner post of my 3-piece airlock. I had to trash my last one after its first use as I couldn't get a couple yeast stains to remove even after soaking it in hot PBW for days. Oh well, a new piece of hose is cheap and good insurance for a clean fermentation.
As effective as fermcap is, I gave up using it over a year or so ago as I felt that when I used it in the fermenters that the beers simply did not maintain their head retention as well as I thought they should have. Not that I had much to compare it to, just a personal bias.