It helps to know things like water parameters and tank size, though from the way you make things sound the log isn't doing anything good. I don't actualy even know what it is, but I would say that unless you're emotionaly attached to this log then just get rid of it and save yourself the hastle.

Thanks IceMountain,
sorry about the lak of information. It's a 25 gallon tank recently with lots of plants. It's in it's final cycling stage. I'm waiting for nitrite levels to get to zero. pH is ~6.5. There's also some malaysian bog wood in there. It's quite a nice piece of wood, the Mopane, and it was kind of pricey so I'd like to keep it.
Cheers
Rodrigo

If the wood is rotting it will continue to add ammonia into your water. If I am not mistaken most bogwood is actually mopane or vice versa. I hate to say it but it may cause alot of trouble that way. Is it possible to exchange it from the place you bought it. If it was sold as aquarium safe it should be guarenteed not to rot. I know someone who had the same issue with a piece of bogwood and insisted on keeping it. He battled with it and finally gave up and removed it. If you truly "need" it, I suppose you can dry it and seal it completely in a marine epoxy that is safe. Make sure you get the kind that dries clear. This may be some work and a little expensive.