Which one should I buy, coarse (12 grit) or fine (24 grit)?
25 lbs. Walnut Shell 12 Grit Coarse Abrasive Media $24.99
25 lbs. Walnut Shell 24 Grit Fine Abrasive Media $22.99
I also looked at Petsmart but they are more expensive and don't mention the grit:
All Living Things® Ground Reptile Bedding 25 dry Qt $27.99