75% organic top soil with 25% filtered play sand is what I use. Works amazing at holding humidity and my nile has really formed burrows with it. I also noticed is you get it too wet it doesn't get swampy because the sand lets it penetrate to lower levels and it soaks in. I tried mulch in the past but if I don't like how it gets so wet when you mist the cage. As far as the other stuff I have not tried it.