By Melinda Burns A long-awaited county Board of Supervisors hearing on cannabis odor control ended in a split vote this week, as three board members voted for more study, and two said they were frustrated by the delay. Dutch-made carbon filters, called “scrubbers,” have been shown to dramatically reduce the smell of cannabis in Carpinteria Valley greenhouses before it can escape into the outside air; but at $22,000 each and a recommended density of 10 per acre, they’re expensive. In addition, electrical upgrades for the scrubbers could cost tens of thousands of dollars more, a “potentially prohibitive expense,” county planners told the board on Tuesday.