Leached tannins aren't dangerous to your tank. You don't need to turn up filtration. Adding carbon will help keep the tank look a little less yellowish but as someone already stated, you will need to change it often for it to continue to be effective. Eventually, your driftwood will not leak tannins anymore. The amount of time this can take though, varies. Mine was a small 12" piece. It took about a month and a half.