I have herd if you put white vinegar in a bucket with water and leave it for a few weeks !! Also Seachem phosguard will clear the water of tannins withing 2 days , I have used phosguard for 2 weeks now with no probs, fish are fine and so are plants . I would recoment useing root tabs instead of liquid fertz as it will remove them very quick. It clears alage up too. Wonder product better than carbon. I stilluse carbon in my home made filter for obvious reasons , give it a try its worked for me , would love some feedback on my comments cheers all.