Refinished Purple Heart Deck originally coated with Messmers. Pressure washed to remove old finish & coated with Cabot Jarrah Brown Australian Timber Oil. Desk now has a prolific white fungus which is basically dissolving the wood . have spare wood outside {not coated} which is fine so stands to reason Stain is the problem. This is a floating deck on a treated 2x4 base which does not have stain on it & is fine. Fungus not evident where deck boards touch the 2x4's. The boards in the pictures have had about 2 in. of the fungus scraped off. This is the bottom of the boards