ᐅ How to Clean Tannin Stains on a Patio?

Hello,
we are currently working on our terrace roof. To protect the paving from potential stains caused by the painted beams, I placed some wooden slats underneath so they don’t rest directly on it.

Now the positive: the paint did not leave any marks. The negative: one of the slats was made of oak wood, and after the rain, it left an unattractive streak on the paving. I couldn’t explain it at first and started searching online... and it turns out: the wood reacts with the alkaline concrete pavers, releasing tannic acid that creates a stain similar to rust. Is there any way to clean this off? Has anyone had experience with this...? Otherwise, I would probably have to replace about 25 stones...

We had the same issue on our beige paving.
Shortly after moving in, our child received an oak sandbox as a gift, which we initially placed on the terrace before selecting a permanent spot and digging the pit. The rain then spread the tannic acid in a clear square shape on the paving.

The good news is that it comes off again. The bad news is that it takes some time.
Scrubbing with water helped a little, but the stain was still quite visible.
I’m not sure if we used any chemicals in the meantime.
What really helped was time, sun, and rain.

I share the same view as the previous poster. I am also not sure whether the stain can be removed with chemicals or other products. In my experience, however, the passage of time, weather, and other factors tend to naturally reduce such stains.

I recently bought a mold remover for about 12 euros, which also advertised cleaning tannin stains, from a major online retailer. The reviews were very promising.

However, I couldn’t test it because the stains had significantly faded within just under two weeks, so I decided to hold off for now.