# new filter in an already cycled tank...how long till filter is good to go?



## nicks7.1985 (Aug 11, 2010)

im setting up another aquarium but already have a nice mature one so i put the new filter (HOB) on the old tank ...I also put the old filter on the new tank...how long should I wait before transferring he filters bac?. I'd leave it as is but the old filter is too small to continuously use on the new tank.
thanks ppl!!

EDIT ..i guess I should have included that I did this because i think it will help cycle the new tank faster...if Im wrong plz let me know 

Nick


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## DishyFishy (Jul 17, 2011)

Ya it will definitely cycle the tank faster. But the NEW filter that you put on your old tank, you should give it about 2 weeks to build up a nice little bacteria colony before transferring.


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## JP55g (May 11, 2012)

you moved the filter from the old tank to the new one, does the old tank have more than 1 filter? If not, you just removed most of the bacteria off that tank.


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## nicks7.1985 (Aug 11, 2010)

no it dosent have a second filter ...i thought all the gravel sub and plants etc...would have bacteria on them?


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## Complexity (Jan 30, 2008)

It depends on how you have packed the HOB filters. If you're just using the manufactured carbon cartridges, then there's not that much bacteria on them as compared to what's in the tank (substrate, plants, hardscape, tank walls). However, if you've packed the HOB with biomedia, sponges, and/or large amounts of filter floss, then you may have moved over a significant amount of the tank's bacteria, depending on the amount of biomedia you used.

The best thing to do is test the water of both tanks to monitor the cycling. That way you'll know if either tank is having a problem and take corrective measures.


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## nicks7.1985 (Aug 11, 2010)

complexity..thats good advise ..thanks. the filters are stock, and they have bio wheels..if that helps. i will make sure to monitor with testing


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## Diana (Jan 14, 2010)

Very roughly:
The filter has more or less half the bacteria, and all the other surfaces in the tank have the other half. In the case of filters with Biowheels, that is where a really big population of bacteria are. Every time you remove the filter media (the cartridge) you are throwing away bacteria. So there is more on the biowheel because it has been developing longer.

Having removed half the biomedia (the filter and all its parts) from the old tank, remove half the bioload, too. Put these in the new tank, where the old filter is. (unless you are doing the fishless cycle in the new tank)

If the filters are not the right size for the tank (too much or too little water flow) JUST move the media, (in this case the biowheel) hang it in the tank somewhere with good water movement or just let it drift. 

Any way you do this, a well established bacteria colony takes time to develop. The bacteria that remove nitrite are slow growing, I would give them at least 2 weeks just to get started, and another week or so to get better established. 

If you are doing the fishless cycle in the new tank that is even better, but watch out in the old tank. Having removed a lot of the bacteria, but none of the fish this tank could show spikes of ammonia or nitrite.


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## 150EH (Dec 6, 2004)

I think is the future it might be better to keep your established tank in tack and just cycle the new tank so you don't run the risk of an ammonia spike in the established tank.

I would use water from the old tank for the new tank when doing regular water changes and squeeze out the filter media from the old tank into the new, etc. instead of cleaning over the sink.

Bio wheels are great for breeding bacteria in large quantities just like a wet/dry filter, so they are a great way to start a new tank if the filters are the same size you can just swap them without taking all the bacteria from the old filter.


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## Complexity (Jan 30, 2008)

150EH said:


> I would use water from the old tank for the new tank when doing regular water changes


Why would you suggest this?

If the idea is to transfer bacteria over, then I don't see any real benefit in doing this since there is very little bacteria in the water itself. The bacteria is attached to the surfaces inside the tank and filter.


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## Diana (Jan 14, 2010)

Couple of ways to go when setting up a new tank:

Fishless cycle, starting with a bare minimum of bacteria from the established tank. For example transferring some rocks or driftwood, or putting the old cartridge in the new tank, or any other way of getting just a little bacteria. Not enough to cause problems in the old tank. 
I have taken as much as 25% of the filter media from an old tank and had not problems. There are a lot of bacteria in all the other places, and the plants help a lot, too. There is not a lot of nitrifying bacteria in the water. Some. Enough to jump start the fishless cycle in the new tank, but not enough that the removal causes problems in the established tank.

Divide the bacteria and livestock in equal proportions. If you take half the bacteria (like moving the whole filter) then move half the livestock. 
If you take 1/3 of the bacteria, like just the biowheel, then move 1/3 of the livestock. 

Plant both tanks heavily, and these rough proportions of where the bacteria live will be a reasonable guide, and the plants are a good cushion. 

In a heavily planted tank with a well established Biowheel and the cartridge is changed out monthly or more frequently we could estimate where the biofiltration is.
Plants: 30-40% Even more if the plants are the fastest growing nitrogen sinks, and are really growing fast. 
Biowheel: 35%-45%
All other surfaces in the tank (substrate, driftwood, rocks...) 15%-20%
Old cartridge (running for a month) 10%

In a non-planted tank then the ratios are more like:
Biowheel: 50%
Cartridge: 10%-
All other surfaces: 40%


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## willknowitall (Oct 3, 2010)

syphon out some substrate and pour it into new tank


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## nicks7.1985 (Aug 11, 2010)

thanks ppl ..thanks for the detail diana ..the old tank isnt too heavily "fished"..5 serpae tetras and 6 zebras in a 37gal tank. I did move the zebras to the new tank a 55gal after reading ur post ...makes a lot of sense


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