That was cool. Intuitively, after years of experience with soil underneath gravel, I think that would work much better than one would think at first glance.

I've noticed that when the soil have aged a bit it settles *very* quickly when uprooting thus not making any cloudiness at all - just a bit of mulm around the area where you uprooted the plants. If mixing alot of sand and just a bit of soil thoroughly it should be a bit like getting a well mulm-infused bottom/substrate in seconds.

I will try this next time I setup a tank.