bogwood / driftwood tannin

Hello,
I have had this piece of wood (Mopani I believe) for about one year now and
it still continues to leach tannins into my aquarium water at the same rate
as when I first aquired it. I've tried boiling it and leaving it sitting in
a bucket which would slow it down for a while, then it eventually starts
leaching as usual.

The tea colored water from the tannins is tolerable... but for once I'd like
"clear" water in my tank for more than a day or so. The only other thing
I've read is that coating the wood in polyurethane (a water based, non-toxic
sealant) can stop this altogether, but removes the natural benefits of
having wood in the aquarium (lowers ph, pleco food etc). Which is not
really a good option, I pick the health of my fish over the tea water...
but I get frustrated when I see displays with clear water and a huge chunk
of real wood sitting in the tank.

Are there any other tricks to speed this up? Or maybe there is something I
can use in my filter to clear the water? (I have a box filter with bio-media
in it btw) Charcoal only helps for a couple of days, then the tannin just
comes back to haunt me again..