Cycling A Second Filter

[Sophie]

Really is just a novice question - My 260L has been fully cycled for 8/9 months now with the Fluval 406. I wish to mature a second filter (Fluval U4 which will work as a second filter for another tank). I've popped it into my 260L. How long roughly do you think it will take to mature? Anything I can do to speed up the process?

 

[TwoTankAmin]

The first thing to understand is that adding the filter will not create more bacteria. it will spread out what you have. Because you are doing this in a stocked tank, there is nothing you can do to accelerate the process. However, if you have the second tank, you can do things differently which would let you speed the process.
 
By taking some media and/or gravel from your cycled tank and putting into the new one, you can then proceed with a regular fishless cycle dosing ammonia. Because you are seeding to start from the existing tank. The new tank will cycle faster than it would otherwise. Plus you do not have to wait for the two weeks or more it would take to get a decent amount of the bacteria living in the new filter before moving it over.
 
In the end, the effect on the established tank will be pretty much the same- you will remove about the same amount of bacteria whichever method you use. The major difference will be in the new tank. It will cycle faster and will be able to handle a full load of fish when its ready. Merely moving over the new filter with some bacteria now on it would mean either finishing up with a fishless cycle anyhow or else stocking almost as if you were doing a fish in one- adding stock gradually.

 

[Sophie]

The first thing to understand is that adding the filter will not create more bacteria. it will spread out what you have. Because you are doing this in a stocked tank, there is nothing you can do to accelerate the process. However, if you have the second tank, you can do things differently which would let you speed the process.
 
By taking some media and/or gravel from your cycled tank and putting into the new one, you can then proceed with a regular fishless cycle dosing ammonia. Because you are seeding to start from the existing tank. The new tank will cycle faster than it would otherwise. Plus you do not have to wait for the two weeks or more it would take to get a decent amount of the bacteria living in the new filter before moving it over.
 
In the end, the effect on the established tank will be pretty much the same- you will remove about the same amount of bacteria whichever method you use. The major difference will be in the new tank. It will cycle faster and will be able to handle a full load of fish when its ready. Merely moving over the new filter with some bacteria now on it would mean either finishing up with a fishless cycle anyhow or else stocking almost as if you were doing a fish in one- adding stock gradually.

I understand all this and thanks.
Shame really. My brain went by the logic that more filter media would mean more bacteria. Especially more biomedia. I wonder why it just spreads out?

 

[snazy]

I wonder why it just spreads out?

 
Because there's just enough bacteria in tank to deal with the current bioload. So you can't grow more bacteria but the advantage of multiple filters in the same tank is that sometimes a single filter may not be big enough or powerful enough to receive enough ammonia/oxygen and water on time to grow the bacteria to full capacity. In this case one can see unexplained ammonia spikes due to the filter not coping.
 
Best is to cycle the filter in the separate tank. It will take just about the same time-4-8 weeks.

 

[Sophie]

I wonder why it just spreads out?

 
Because there's just enough bacteria in tank to deal with the current bioload. So you can't grow more bacteria but the advantage of multiple filters in the same tank is that sometimes a single filter may not be big enough or powerful enough to receive enough ammonia/oxygen and water on time to grow the bacteria to full capacity. In this case one can see unexplained ammonia spikes due to the filter not coping.
 
Best is to cycle the filter in the separate tank. It will take just about the same time-4-8 weeks.

Fair enough now I know, thanks
Would it work if it wasn't established? Or if I add more fish and then transfer filter and fish to second tank? Confusing I know. Trying to get my head round it all

 

[snazy]

Would it work if it wasn't established?

 
Not sure what you mean. A non established filter is an uncycled filter so it won't do anything for ages.
If you add more fish, more bacteria will grow in both filters, but you never know in which one how much, so taking one out can't guarantee that you won't end up with an ammonia spike in at least one tank depending on the bioloads left in the tanks.