# cycling a new tank with established gravel/filter



## ginagv (Oct 26, 2010)

I am in the process of setting up a 55 gal aquarium. I have a 20 gallon that has been up and running since April 2010. My intention is to use the current gravel (and add new sand also with it) and the filter medium from the current hob filter in the new (larger) filter along with new filter pads. If I use that, the old water as well as new conditioned water, will I have to wait for the tank to cycle? I would not be increasing the bio load right away.

I know this is probably a stupid question, but I don't want to lose any fish I already have unnecessarily. I have cherry barbs, Otos, and cories... oh and a bajillion MTS....

thanks,

Gina


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## mjbn (Jun 22, 2010)

I'm a bit confused with your technique. Are you gonna put a new filter cartridge in your OLD filter? Don't ever replace the cartridge until it is basically falling apart or completely clogged. It holds a huge amount of bacteria that you don't want to lose. If you use gravel from your old tank and float it in your new tank, it will seed it. If you are able to run the old filter in the new tank, it will as well. It would be better if you could get some filter media from your old tank and put it behind the filter cartridge of your new tank.


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## ginagv (Oct 26, 2010)

Hi sorry,

I guess I wasn't clear. The new tank's area for the gravel is obviously bigger and I was planning on just using it in the new tank as is, adding some sand to make up the difference to get a good bed. Then I was going to add the old filter pads into the new bigger filter in addition to the new pads that are made for the new bigger filter. If I do that, and use the water I have in the current tank, and add the remaining 35 gallons (20 gallons plus 35 gallons make 55 gallons) of fresh but conditioned water, would I have to wait to cycle or could I move my present fish over immediately too?

Sorry its late... but I'm excited!

Gina


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## Kazzy (Dec 14, 2010)

I believe that could work. The beneficial bacteria mainly grow in the filter, gravel, and decor. I would just run both filters on the new tank though just in case. And keep a very close eye on the water parameters.

Just be sure that the filter media, gravel, and decor don't dry out and that the new water is conditioned of course.


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## 1077 (Apr 16, 2008)

If you are wanting to keep the smaller tank running (quarantine good idea)), then so long as you don't remove more than 50 percent of the filter material ,what you are planning should work. If your not going to keep both tanks running,then I too would let both filters run on the new larger tank for a couple three weeks and then remove the smaller one.
Just be sure to add any new fish slowly ,and a few at a time to the new larger tank to allow bacteria to gradually increase with the gradual increase in numbers of fish.
Were it me,,I would try and keep the smaller tank running if new fishes are being considered for the larger tank. Would be sure and add a few fishes to the larger tank at the same time that I added the borrowed filter material or gravel to provide food source for the bacteria that you transferred. If new fishes are being considered ,I would leave a few fish in the smaller tank until i purchased a few new fish and then remove the few fishes from the smaller tank to the new larger tank and place the new fishes in the old tank as quarantine (wise). Hope this makes sense, Whenever bacteria is alive,,it needs a food soiurce (fish food ,or fish waste) or withinn 24 hours,,it will begin to die off depending on water conditions ,and the amount of bacteria present.


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## tanker (Mar 13, 2010)

I swapped fish from a 75-litre to a 165-litre. I used a cup of "dirty" gravel and rinsed out the rest and augmented it with new gravel. I put the filter pads from the small tank into the filter on the bigger tank with the new pads that came in the bigger tank's filter. I used completely fresh water in the new tank. In other words, I did what you are proposing except I didn't use the old water and I only used a bit of mucky gravel and took the opportunity of getting the muck out of the rest. The new tank was also planted with live plants. 

I didn't get any ammonia or nitrite spikes, everything just seemed to continue on as before. I didn't add anything new for about a month or so. (The old filter pads are still in there, I need to list my small tank for sale and I can give them to the buyer if I sell it.)


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## ginagv (Oct 26, 2010)

thank you Tanker, I appreciate your taking the time to answer my question. 


Gina


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