I also just discovered 'ReptiZorb' liners for the ARS tubs. I ordered some for the hatchling rack, my 5040 rack and my 7030 rack to try them out. Apparently they are like super absorbent felt paper that's pretty stiff. Should work good in the trays with the cup holders to keep them in place. I'll probably put coconut husk in there only when a snake is in shed to boost the humidity. Seems like cleanup would be easier with these pads in the tubs. I'm always on the hunt for the best substrate LOL. Especially now that I'll have an additional 39 tubs.

https://superiorshippingsupplies.com...0-count-28-ea/