Seems to have the same effect as oxalic acid. I have quite a large balau deck, even after removing half the thing. Used to maintain by sanding (this broke me each and every time) and using Woodoc deck dressing but it never looked great. After a lot of research I've switched to cleaning with a high pressure hose every few months, a quick clean with oxygen bleach followed by applying a boiled linseed oil/turps mix. Made my life so much easier and the deck looks great! If the deck ever goes a bit grey or weathered, a quick application of oxalic acid has it looking like new.