BOBO started this when I moved on the island in 1998. The time depends on water temp. It takes a little longer when the water gets cold. 35 days in October/ Nov. and about 50 to 60 days in January.
When done I just hose off with garden hose. Sometimes I get couple barnacles that I just scrape off with a knife. But this is when submerged for for the 60 days.
I do bleach over night with about a 10% bleach content in water.