The bags you show in the photo are clay litter -- not crystals. These will not work properly in a Scoop Free box, and will actually damage it.
My neighbor (who uses this system) recently went on vacation and we were taking care of their cats, and the first time in to check the box I was...
The answer is no, rigid PVC (which is what the Forever Trays are made of) is not poisonous, contrary to what the makers of the Permascoop would like to scare you into believing. The compound in question is "phthalates" -- used to soften PVC, which is not found in rigid PVC.
Don't just take my...
