Ok, i bought myself a used unit that consists of a steel tank, some hoses, a spray wand, and a gear pump that is attached to a honda 5.5 engine. There is still some sealer in the tank but it's pretty thick and i think from last season. I keep hearing alot of things about this BLACK MAC stuff. Is it the product of choice and where would I acquire it? I don't want any cheap stuff as I'm looking for a quality product to build the business on because i beleive good service is already present. Thanks! All advice is welcome!