I just moved our three 8 month old Russians that hatched in the yard last summer, into a larger container (they are now 3+inches long), for new bedding I used Sungro Black Gold Orchid Potting Mix from Ace Hardware. The ingredients listed in the California version are; Fir bark, Pumice, perlite and wetting agents. They immediately went for the small crunchy bits (pumice?). Is this normal or dangerous? Thanks