Turf scrubber is a special filter using fast growing turf algae as an export method. It was/is patented by Dr. Walter Adey and was more popular in late 90s. In recent years people have been moving towards growing macro algae in refugiums (another method originally developed by Dr. Adey)
More info here: :: The Algal Turf Scrubber ::
More info here: :: The Algal Turf Scrubber ::