waterdrop
Enthusiastic "Re-Beginner"
OK, Let's talk about carbon some more since its a question of both DaveyG and fishnoob88.
Carbon (aka activated charcoal and a few other names perhaps) has come to occupy an unusual place in the world of aquarium filters. Technically, its considered a "chemical" media, which is one of the three major filtration functions: chemical, mechanical and biological. In reality, many types of media will overlap on these three functions and carbon is no exception. Carbon will also serve as a good surface for bacteria to build their biofilms on and will serve as a good mechanical filter if enough volume is used to form a good layer. But carbon is not really the winner in the race to be the best for these functions. Sponges and ceramics win out as the best biological media and that is partly because carbon will eventually crumble. In fact it is constantly breaking down a bit and little pieces of it are carried away, with the even smaller bacteria hanging on, to go out with the water change or whatever. In contrast, sponges and ceramics are not crumbly and are more durable.
The real value of carbon is when its used as a chemical media. Carbon "adsorbs" chemicals by the use of molecular charge attraction and has a vast surface area for containing the chemicals that stick to it from this. Its main uses by aquarists are to adsorb medications after they've been used in the tank, to adsorb yellow tea-like tannins when they've been introduced usually via new wood ornaments and finally, to adsorb the organic chemicals that have caused odors that might be giving off the rare but occasional organic smell of unknown origin. It takes carbon only about 2 or 3 days to adsorb all that it can and then it needs to be removed and thrown in the trash and replaced with more carbon if the goal has not been reached yet.
For these reasons, carbon is a great thing for the experienced aquarist to have "on the shelf" ready and waiting (shelf life should be very long if you keep it enclosed) in the supply closet. But its not needed in the normal running of a filter and would be terribly expensive if it were. And therein lies the reason for its popularity in the manufacturing and retail side of the hobby. Its a media that can't really be criticized as being bad, but beginners will feel they need it and it is one more item that can help provide some steady sales from the stock shelves in the retail store. Anyway, that's the story: it can do great stuff, but its good to get the whole picture.
So to touch base again hopefully with the specific questions: Davey, I'd say you've got a couple of options that would work for your gravel. You'd be fine after a month removing it from the new filter and allowing it to fill back in as gravel in your biube (you can rinse the debris off in tank water and the bacteria will remain tightly clinging to the gravel even though you can't see them for the most part. fishnoob88, Yes, there will be plenty of bacteria established on the carbon of an established filter and so moving one of those carbon packs over would do fine as a seeding technique. And for both of you, from fishnoob88's question specifically, you should always try to give things about a month when you want established bacteria to spread from existing media to new media within a filter or between filters in a new tank.
~~waterdrop~~
Carbon (aka activated charcoal and a few other names perhaps) has come to occupy an unusual place in the world of aquarium filters. Technically, its considered a "chemical" media, which is one of the three major filtration functions: chemical, mechanical and biological. In reality, many types of media will overlap on these three functions and carbon is no exception. Carbon will also serve as a good surface for bacteria to build their biofilms on and will serve as a good mechanical filter if enough volume is used to form a good layer. But carbon is not really the winner in the race to be the best for these functions. Sponges and ceramics win out as the best biological media and that is partly because carbon will eventually crumble. In fact it is constantly breaking down a bit and little pieces of it are carried away, with the even smaller bacteria hanging on, to go out with the water change or whatever. In contrast, sponges and ceramics are not crumbly and are more durable.
The real value of carbon is when its used as a chemical media. Carbon "adsorbs" chemicals by the use of molecular charge attraction and has a vast surface area for containing the chemicals that stick to it from this. Its main uses by aquarists are to adsorb medications after they've been used in the tank, to adsorb yellow tea-like tannins when they've been introduced usually via new wood ornaments and finally, to adsorb the organic chemicals that have caused odors that might be giving off the rare but occasional organic smell of unknown origin. It takes carbon only about 2 or 3 days to adsorb all that it can and then it needs to be removed and thrown in the trash and replaced with more carbon if the goal has not been reached yet.
For these reasons, carbon is a great thing for the experienced aquarist to have "on the shelf" ready and waiting (shelf life should be very long if you keep it enclosed) in the supply closet. But its not needed in the normal running of a filter and would be terribly expensive if it were. And therein lies the reason for its popularity in the manufacturing and retail side of the hobby. Its a media that can't really be criticized as being bad, but beginners will feel they need it and it is one more item that can help provide some steady sales from the stock shelves in the retail store. Anyway, that's the story: it can do great stuff, but its good to get the whole picture.
So to touch base again hopefully with the specific questions: Davey, I'd say you've got a couple of options that would work for your gravel. You'd be fine after a month removing it from the new filter and allowing it to fill back in as gravel in your biube (you can rinse the debris off in tank water and the bacteria will remain tightly clinging to the gravel even though you can't see them for the most part. fishnoob88, Yes, there will be plenty of bacteria established on the carbon of an established filter and so moving one of those carbon packs over would do fine as a seeding technique. And for both of you, from fishnoob88's question specifically, you should always try to give things about a month when you want established bacteria to spread from existing media to new media within a filter or between filters in a new tank.
~~waterdrop~~
