I bought a big peice of Malaysian driftwood the other day, boiled it for an hr to remove microorganisms and some tannins. I decided to remove the rest of the tannins through water changes. I use my old Marineland Penguin filter cartridge frame to make my own cartridges. However.... I added API Activated Carbon to the filter and it doesnt sizzle when it touches the water the way the stock Marineland cartridges do. Also... it must have been at least 17 hrs by now and the water is still tea colored from tannins. Does the API activated carbon not work? And how come the Marineland's carbon sizzles and the API's doesnt...