From your previous thread you arent cycled, so you dont have much beneficial bacteria to lose. I would just get it over in one go. A more cautious approach would be to gradually replace the cartridges 1 a week, there are 4 cartridges in your filter from recollection. You will have to look at your filter and see if that is something you can realistically do.
As for carbon. Carbon removes organic compounds. This is typically
- Tannins from driftwood which colour the water and make it tea like.
- Phenols that cause odours.
- Medication.
Tannins are temporary. Once they have leeched out they stop effecting your water.
If you keep up with your water changes you shouldn't get smells
Medication is a temporary situation.
So, use carbon for its intended purpose. Then stop its use. Once any tannins has leeched out of driftwood, remove any carbon. Keep up with your water maintenance and you shouldn't get smells. If you need to medicate use carbon to pull it out of the water once the medication period is over.
Carbon is expensive, only lasts a couple of weeks before it needs replacing and most of the time isnt really doing anything of benefit. You dont need it in the filter all of the time.
Many people will advocate its use all the time and say it removes ammonia, nitrite and nitrate. This is a misunderstanding of what carbon will do. It will remove some organic compounds before they break down into ammonia, but doesnt actually remove ammonia. In a cycled tank, the nitrogen cycle will remove the ammonia anyway. Some people say it keeps their water crystal clear. IMO their water would still be clear without it. Running carbon all the time wont hurt anything, and if you can stand the expense that's your choice.
