Review on Marineland Black Diamond Premium Activated Carbon: Top-Quality Filter Media for Aquariums in Blacks & Grays (10 Ounces) by Brandi James

Got about 2 handfuls for my 55 gallon tank and this stuff quickly started to work. At night (7+ hours) I had clean water. After 2 days it was crystal clear. I've used others, good and bad, but for the price and quality of Marinelands Carbon I think I'll stick with them. As for how long it works my advice is to use it a little at a time for a maximum of 7 days and take it out. and use again when you notice a slight cloudiness instead of adding more and leaving it in the tank for a month+ as some others recommend. Especially for beginners it doesn't let you forget and a whole lot of stuff is backwashed from more carbon than just a little bit. I also found it more efficient and effective.