Contact Prant products Ltd at
http://www.plantprod.com/EN/contacts.html#customerservice
They are the Canadian distributors for turface, and could point you to a local supplier.
Also your local farm co-op (if any in area) usually have chicken grit. Make sure it is the decomposed marble type, (not oyster shells); and get the hen grit as it is the best size to use as an amendment. Just note that the grit makes your pots very heavy