My composite deck has cedar rails, for esthetic reasons. I know, I know,
don't bust on me.

I've treated the rails with Austrailian Timber Oil, which did a wonderful
job at keeping a red hue while showing all of the grain.

Problem is, mold has grown on it like crazy.

Could I add fungicide to it? ATO is an odd beast and supposedly cannot even
take a tint added to it.

Or should I just punt ATO entirely and go with Cabbot, like everyone else in
the world seems to like for outdoor stuff ?