Fluval Edge 23l

Hello.
I need some advice for my filter.
I use a sponge, carbon, and Biomax. After reading a few posts am I correct in thinking the carbon is unnecessary and may even be a hindrance. The tank has been running about 3 weeks now.

Thanks

Jesnon has beaten me to it  She is the one to ask about details of the tank as she has one herself.

Carbon isn't necessary on a routine, it's a hang over from decades past. But you can still use it you want to.

Carbon adsorbs things, but it gets used up fairly quickly. It is also a home for the filter bacteria (which is why I say to change it now if you intend doing so, before it has chance to grow many). The problems with carbon are:
it does stop working after a few days so it you do want it to remove something like the brown colour from bogwood it has to be replaced frequently.
carbon granules crumble over time, so if you don't bother changing it the granules will slowly dispappear
carbon does adsorb medication, which is why the bottle of med will say to remove any carbon before use. If it is old carbon, it will be full but the danger is that the med could be more strongly attracted to the carbon than what's already on it, and displace the old stuff. But  lots of people have no problems treating sick fish with old carbon in the filter. It's new carbon that would definitely remove meds.



You said in another post a couple fo days ago that you don't have fish yet. Are you doing a fishless cycle (with ammonia or fishfood) or just waiting till you find fish you want and will then do a fish-in cycle? Depending on exactly what you are doing and where you are up to (if it's fishless cycling) now might well be the best time to swap the carbon for more sponge or biomax if you choose to do that.

If you get fish today, you will find yourself doing a fish-in cycle. Every report I have read on Nutrafin Cycle says it does not work. And even if it did, you would have to add a source of ammonia as well to feed the bacteria.

There are only 2 bacterial starters that are reputed to work sometimes and they are Tetra Safe Start and Dr Tim's One & Only (if you can find it in the UK). But even they need ammonia to get the bacteria to grow, and they do not cycle a tank instantly. And they don't work every time.

Can I suggest you read this to see what you will be letting yourself in for if you get fish today.

With a tank the size of the Edge, you are very limited as to what fish you can have. Most of them are tiny shoaling fish, but a shoal of even the tiniest is too much for a fish-in cycle. Your tank is 6 American gallons and the maximum for a fish-in cycle is 1 inch of fish per 5 gallons. So the maximum amount you can get is fish with an adult size adding up to 1 and a bit inches.

Do you have a liquid reagent testing kit? You will need one to do a fish-in cycle if you get fish today. If you decide to do a fishless cycle, you will also need one.

You'll find it hard to source Dr Tim's in the UK as it's American, but Tetra Safe Start is available here (assuming you are in the UK). But even if it works (not guaranteed) it won't cycle a tank on its own. People report doing a fishless cycle in as little as two weeks using it when it takes about 6 to 8 weeks without. You will still need a source of ammonia whether it's ammonia solution/fishfood in a fishless cycle or fish, in a fish-in cycle.



HAve you decided what fish you want to get?

I thought better of getting fish today. So I'll cycle the tank without fish as it seems safest/ easiest. And I haven't decided on fish. Choice is quite limited where I live, there is a local supplier about 40 minutes away and a Pets at Home closer. And I realise the tank size is restrictive.
I like Neon Tetra, and Siamese Fighting Fish, but I certainly haven't made any choices yet.