I was thinking about using that method, but instead of using perlite I was planning on using vermiculite as I had just bought a huge bag from HD. The only problem with the vermiculite is that it tends to float on top of the water. I'm not sure if that would be a problem, but I haven't tested it long enough to see if the top layer of the vermiculite would dry out and form a crust. I might just end up using the perlite as that is the only way I've seen the no-sub method used.