I got a pair of Mardonius millipedes a few weeks ago and for the first week I had them I used a substrate of Zilla Jungle Mix and sphagnum moss until the Josh’s Frogs Milli Mix that ordered online arrived. I just found out that the fir in Zilla Jungle Mix could be bad for millipedes. If so, how concerned should I be about the week they spent in that substrate? Is fir toxic to them, or is it just not very nutritious? Any advice would be appreciated.