Ground English Walnut Shell Substrate

Question
Hello, I breed my own Leopard Geckos and I currently use All Living Things brand of white Calcium Sand for a substrate for my three females that are in a 40 gallon reptile tank. I recently got a new tank that is the same size and I am debating on the substrate. I have never had any problems with the calcium sand that I am using now. It is not super fine and is about 1/5th to 1/8th of the size of aquarium gravel. My Geckos have never had a problem with it and seem to like the texture of it. In my new tank though, I have been thinking of putting Zilla's Desert Blend Ground English Walnut Shells. I know that there is crushed walnut shells out there that have sharp edges and that are much larger. The Ground walnut shell substrate that I am looking at using is fine and much smaller than the calcium sand I am using.

I wanted to know your perspective on what I should use. I don't like the look of slate or tile in the bigger terrariums just because i feel it takes away from the effect of the big open space for them to explore on and i feel that loose substrate would be much more comfortable than hard tile. Plus when they are gravid they wont have anywhere but a hide-box to dig around in. I feel that it gives the leopard gecko more freedom to dig around all over the cage and choose where to lay her eggs verses just giving her one option. I do use Repti-Carpet for the two ten gallon tanks I have for the hatchlings and the male to have a home in, though.

But anyways, I have heard a lot of debate about the bacteria buildup in the Ground Walnut Shell, as well as impactation, and eye problems. Now it seems like a lot of people see walnut shells and automatically thing crushed big pieces. This is not the case, what I will be using is the sand-like, Ground Walnut Shells.

Thank you for everything in advance!
-Josef

Answer
Josef, thanks for your question. I personally don't recommend either substrate that you use if I am honest. The calci-sand is known to bind up in reptiles when eaten. The walnut shell can swell and is as you mentioned often times sharp. I used washed play sand for all my desert dwelling reptiles. Here is a link to an article where I break down all the substrates that I use http://bit.ly/WCCasE