I'm 75% finished with my oak enclosure for my cali king and bp (housed in two separate but stackable units) and am trying to decide what substrate to use. I've been using newspaper in their cages up until now, but after putting so much effort into their new custom display cage, I want something a little more aesthetically pleasing.

I was thinking about using Zoo Med Repti Bark. What have been your experiences with it?

Also, would it be advisable to use a substrate such as Repti Bark with my king snake? I know he needs a lower humidity than my bp and wanted to know just how much Repti Bark affects humidity. What would be some other good dark colored substrate alternatives for the king snake (coconut husk, Eco Earth, etc)? I do not find aspen to be all that pretty to look at (the lightness of it clashes horribly with the red mahogany color of their enclosure) and am hoping there's something else I can safely use