How to cycle a new 10 gal tank (have existing tank)

eliza4fish

Member
Hello again,

I just bought a 10 gallon tank and I was wondering how could I speed up the cycling process if I already have a fully cycled, 20 gallon tank? I havent changed the filter yet in my 20 gallon (cleaned it once in old tank water) and I've had it for 2 months now. Could I take the filter media out and use it to cycle my 10 gallon tank without disrupting my old tank? I want to move my betta into the 10 gallon so that he doesn't get stressed from my other fish (3 platies), and I would like to move him asap if thats possible. Or if things improve, I would use it as a quarantine tank. Any info would be greatly appreciated, thanks!
 

Dunk2

Member
You can use some of the media from your 20 to at least jump start the cycle for your 10.

Don‘t remove all the media from your 20. . . You’ll lose the cycle on that tank. And don’t replace the filter cartridge until it’s literally falling apart. Swish it around in water removed from your tank.
 

KayBee3

Member
You can either place the new filter on the old tank for a few weeks to transfer beneficial bacteria into there, or you can take a piece (not the whole thing) of filter media from your cycled tank and place it into your new tank. The latter is basically an instant cycle start. You're transferring already colonized bacteria into the new tank, so that when fish are added, the bacteria can start feeding on the ammonia produced and colonize the new filter.

Both of these methods will not fully cycle your tank however. You may still have some ammonia spikes that you'll want to watch out for with a test kit. Keep up with water changes throughout this process to avoid exposing your fish to too much ammonia.
 
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eliza4fish

Member
Dunk2 said:
You can use some of the media from your 20 to at least jump start the cycle for your 10.

Don‘t remove all the media from your 20. . . You’ll lose the cycle on that tank. And don’t replace the filter cartridge until it’s literally falling apart. Swish it around in water removed from your tank.
Thank you for the clarification, and for your advice!
KayBee3 said:
You can either place the new filter on the old tank for a few weeks to transfer beneficial bacteria into there, or you can take a piece (not the whole thing) of filter media from your cycled tank and place it into your new tank. The latter is basically an instant cycle start. You're transferring already colonized bacteria into the new tank, so that when fish are added, the bacteria can start feeding on the ammonia produced and colonize the new filter.

Both of these methods will not fully cycle your tank however. You may still have some ammonia spikes that you'll want to watch out for with a test kit. Keep up with water changes throughout this process to avoid exposing your fish to too much ammonia.
Thank you for responding to another one of my posts! I feel like I have a million new questions everyday haha. I'm going to try to take a piece of my existing filter and add it into my 10 gallon tomorrow. Could I also add in some of API Quickstart to speed up the cycling process and ensure that its relatively stable before I add my betta? Again, thank you!
 

KayBee3

Member
Hi again,

There's debate around quickstart and if it really helps a cycle or not. I would say go for it, it definitely can't hurt!
 

Momgoose56

Member
eliza4fish said:
Thank you for the clarification, and for your advice!

Thank you for responding to another one of my posts! I feel like I have a million new questions everyday haha. I'm going to try to take a piece of my existing filter and add it into my 10 gallon tomorrow. Could I also add in some of API Quickstart to speed up the cycling process and ensure that its relatively stable before I add my betta? Again, thank you!
Moving a cup or two of the substrate over to the 10 gallon will transfer a good amount of bacteria over too and should help.
 
  • Thread Starter

eliza4fish

Member
Momgoose56 said:
Moving a cup or two of the substrate over to the 10 gallon will transfer a good amount of bacteria over too and should help.
Oh wow I didn't even consider that! It looks like all my fish are getting along again.. but I'm still planning to cycle that 10 gallon this weekend in case anything changes. I'll definitely try adding some substrate when I do though! Thanks so much!
 

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