Hi, in an attempt to simulate a Blackwater environment for my neons I added around 25 alder cones to my circa 70 litre tank. As expected the water turned a lovely tea colour with a matter of hours. However the staining seemed to magically fade within days, so by the end of the week it was almost back to normal. Question is, where did my lovely tannins go. Nothing was added/taken from the tank except fish food and Easycarbo. Do plants use up tannins or is some chemistry afoot?