Carbon filter, to use or not to use?

I only use Carbon as needed. It is a chemical filter and expires in time with use, or gets "exhausted" reaching the limits of its benefit. To be effective it needs replaced again and again, and if left in the tank for extended periods without replacement, it stops working and with enough time, can even release phosphates and other elements into the water!

I use it to remove discoloration or medications if needed, or if I have animals that are known to release toxins. Otherwise it really isn't needed, can be a waste of money to constantly replace, and can actually be a detriment if never replaced.

Carbon only stays activated for so long, then becomes useless, it is a good thing to have, though. I'd rather use it when I need it instead of wasting it. It gets out tannins from drift wood and medications. Its useful, but not all the time. I like the Fluval Biomax Media and PreFilter Media.

No you don't really need one.