Bulking Material mix for Sun-Mar composting toilets. Compost Sure comes in an 8 gallon (30 Litre) bag. It consists of a biologically active mix of coarse peat moss and chopped hemp stalk. Compost Sure has an added advantage over homemade bulking material – hemp. Hemp will decompose where wood shavings and peat moss do not – giving your compost a longer residency time. More importantly, it saves you the time of making your own mix. To use: 1 cup per person per day (average), or 1 cup for every bowel movement.