I just wrote down what was on the container, Ive never heard of it being used for tannins either but he showed me some tubs of goldfish he had which he used it in, Ill ask him next time how long it took. I suppose its until the tannins are completely leached from the driftwood. But ill definately re-tie the plants, and soak the driftwood in hot water on the weekend..
I would leave the tannins in there, but Im trying to make it a nice and perty display tank of sorts for the loungeroom :)