Not sure if this would help you. Sounds like this cleaner (or a similar called alumabuff) and a power washer is a good start.
If you have to grind the barnacles off you might consider a media blaster. I don't know what the best media might be as there might be something a little softer than sand to use a abrasive to break loose the flecks.

If the flecks/hard depositis are iron or calcium/hardness spots then one of the stronger lime removers (CLR Calcium lime rust remover) or WINK brand iron removal which is just hydrofluoric acid might help loosen the debris first.

I can't get a youtube video to embed anymore. Did someone get this feature working again and what am I doing wrongly?

Here is the link:

Pontoon log cleaning

another product:
Purple Power

Last edited by canyoncreek; 12/13/21 04:06 PM.