It is a lovely piece of wood. I'd find a big tub to put it in and just leave it to soak.
I second that. Set it and forget it. Some woods take longer than other to become water logged and/or leech free. Some woods never stop leeching tannins. My water is never crystal clear as there is always a pinch of tannins after a day or two of a water change.
I remember letting my wood sit for a month or two outside in a 32g trash can. I changed the water maybe 3-4 times and that was it. My water ain't free, lol. To help with becoming water logged you can drill holes thru the thickest parts of the wood. If your worried about appearance, do it from a side you won't see.
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