my pump doesnt have carbon inside it but does have a space for it, i was just wondering if because i have none, then my fish ill die once i get them or it will be harmful to them, do you recommend that i get some
Only useful for removing meds, tannins and if you're just starting out. I put filter floss in the area the carbon sleeves usually go to let bacterial build up and to catch the waste.
what kind of filters are you talking about, because i have a whisper 10 and i was wondering if i took the carbon out and just had the mechanical filter if my filter would work the same.
Carbon is only necessary if you need it. If your tank smells it may help, but it won't help you figure out why your tank smells in the first place - it shouldn't. It can also help clear discolored water, from tanins and such. It's good for removing meds as mentioned. Otherwise - don't worry, you'll find no difference with or without it.
Your tank should smell though. Slightly fragrant like a pond. If it's foul or nasty though, then you have a problem. Carbon isn't that important to an established tank in most cases.
Don't leave the filter in though once you replace it with another substitute for your bacteria to grow on (3-4 weeks). The carbon will eventually start to leak out the nasty stuff it kept in and it won't catch the more solid wastes either. Replace it with a sponge or filter floss. I got a huge bag of it a year ago and I use it on 4 filters, still haven't used it up yet. A sponge is better but whatever you use, it still needs to be rinsed (either in used tank water or safe for the tank water) to remove the built up waste material. Both are cheaper than filter cartridges but last far longer.
Carbon is bad during a cycle. It removes the ammonia and nitrites that are needed to establish the bacteria in your tank. It will take approximately one month to let the cycle run.