I am currently in the process of putting together a living natural terrarium for my Ball Python. I have been following the advice of a very helpful and informative book by Philip Purser called "Natural Terrariums" (go figure, lol). In this book it breaks down the various things (substrate, plants, heat, humidity) for a number of different types of terraria (desert, woodland, grassland, etc) and the animals best suited for them. They suggested a grassland setup for ball pythons. For the substrate they suggested: 2 parts ground coconut husk (coir), 1 part sand, and 1 part composting leaves.

At the moment I am stuck on the sand. In the book the warned against using Calcium Carbonate sand because as you water the plants it will cause the calcium to leach into the soil and severly alter the PH levels of the soil. I have also read numerous times that silica sand should absolutelly not be used with herps, especially snakes.

My question is, are there any sands I can use that are not calcium carbonate or silica based that would be safe to use? I have found ground english walnut shells. My question with these is how long will it take for these to break down?

I apreciate any advice.