The whole course only take one hour and no need for a water change. MinnFinn and NeuFinn Koi Pond won Pond Trade Magazine Product of the year award in 2009 Many DlSEASES can be finished in as little as 1 to 3 Courses. The Minn Finn breaks down itself into water , leaving the formula good for humans, pets, fish, wildlife, and the environment. MinnFinn does not discolor water and does not require water changes.