Fosberdmarc.....Any pet store,fish or reef supply company,or shop....Use a higher grade carbon,If it has a happy fish,or smiling fish on the container,stay away from it,,,If it has the name Seachem,Kent or two little fishes you should be alright,,lightly rinse it and put it in an area that water can flow through it...You don`t want to pulverize or have it tumbling or being ground together,a little goes along way,so you don`t need to use a lot,some people change half the amount every month,others change it completely out,there really is no right or wrong answer,but the one thing that is agreed on by both sides is that if you leave it for a very long time it can discharge what it has taken out back in the system,and no you can not reactivate it in your oven,many have assumed or thought that they could....It takes out different compounds that discolor the water,and different ones that make the water smell ,and also possible toxins and growth inhibitures,it helps the protein skimmer as in it also mechanically filters the water,but remember that the skimmer takes the compounds out of the tank,the carbon binds different compounds in it`s internal structure,bacteria grow all over and in the matrix that is carbon,,,It can remove trace elements,but it must be said that a skimmer also removes trace elements,,But the main thing that must be asked,,Do you want a tank full of trace elements,or do you want a thriving tank...a lot of the mess bags that people put on their tanks like chemi-pure,bio-chemzorb all contain carbon,,and putting some on a tank wont make the skimmer go nuts like when you put other chemical filters on your tank...Hope this helps.......
