Instantly Cycling a Tank With Filter Media

mattgirl

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You have gone through the long drawn out cycling process on your first tank and if you are like most of us you will soon decide you need another tank. With a little pre-planning you never have to go through the long cycling time it took to cycle that first tank.

To instantly cycle another tank you can move extra media from your cycled tank over to the new tank. The amount of bacteria on that media will depend on the bio-load of the tank. Meaning how many fish and how much ammonia each of those fish produce. As long as the bio-load in the cycled tank is higher than the bio-load in the new tank you can achieve an instant cycle.

The amount of bacteria on that media is going to depend on how much food (ammonia) the fish have produced. You can't expect much bacteria on the media if the tank the media is coming from only has one or two small fish. There won't be enough bacteria to handle the bio-load of 3 or 4 fish. There may be enough to jump start the cycle much like bottled bacteria does but you won't get an instant cycle.

To accomplish an instant cycle the mother tank needs to be well stocked and well established. I wouldn't expect to be able to instantly cycle another tank from a tank that has just finished cycling. Bacteria grows on everything in our tank. It takes time for the bacteria to grow strong colonies on everything. The strongest bacteria is going to be where the most water movement is. It grows quicker and better on our filter media because the filter is pulling the ammonia laden water through it so the bacteria is getting the most food in the filter. It takes time for the bacteria to get well established. Getting too aggressive at cleaning anything in the tank until the bacteria is well established can cause a cycle to, maybe not crash but can suffer and cause a mini-cycle. Removing too much media from a newly cycled tank can also cause a mini-cycle.

Once a tank is firmly established we can get a bit more aggressive with cleaning, up to a point. We can remove media once a tank is well established without removing too much because it will be growing everywhere in the tank and will quickly replace what we have removed. When I say with a bit of pre-planning I mean we need to run extra media in our cycled tank that can be removed while still leaving enough for the cycled tank.

If we are just upgrading our tank to a bigger tank and not keeping the original tank up and running we can just move the cycle over to the bigger tank and the bigger tank will be instantly cycled. To do so just move EVERYTHING from the small tank over to the bigger tank including the fish and water. The water won't have any bacteria in it but it is the water both fish and bacteria are used to. As long as we aren't adding more fish, thus a higher bio-load, than we have in the smaller tank both fish and bacteria will just think they have had a nice partial water change. The cycle doesn't care how much water there will be in the bigger tank. The amount of water doesn't matter. What matters is the bio-load. Same number of fish = same bio-load = instantly cycled to the bio-load of the original fish. More fish can be adding but added slowly to allow the bacteria to catch up with the higher bio-load.

Edited to add: You will know you have successfully instant cycled your tank if you don't get an ammonia reading after adding fish to produce ammonia or if going fishless the ammonia you add goes straight through to nitrates. You should never get a nitrite spike either way. If you do get an ammonia and/or nitrite spike you will know the bio-load in the new tank is higher than it was in the tank you took the media from. Even if you do it should be short lived since bacteria grows quickly when you start out with some from a cycled tank.
 
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faydout

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I always keep a media bag of bio media hanging under my HOB, an aquaclear 50 sponge tucked behind a sponge filter, a spare floss pad tucked into one of my HOB's, and sometimes, I'm cycling a spare sponge filter. I try to always make sure I can throw a new HOB together in a moments notice for hospitalling, or random "had to have it" trip to the LFS, for a qt tank. My current qt tank is going from 2 little fish to 12 little fish today, I'm just going to replace the sponge in the HOB, with one running in my big tank's filter. The one from the QT tank is going in the trash, not the big tank. Media / water only go one direction in that regard... main tank to qt tank. I like to put some water from the big tank (not the gravel vac water) in the qt tank every week to make sure they're as acclimated to the big tank as possible when the time comes. My nitrates stay below 10 in the big tank, so I don't sweat adding in more nitrates, it's only about 2.5 gallons or so.
 

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I'm ready to start moving everything from my 10g to my 20g long tank. Since I'm going to use the same tank stand, I need to move the 10g first and add the 20gl on top and put the 10 on the bottom of the stand. These are some steps I think I could do to start. All suggestions/advice is accepted!

To move the old tank, drain about 80% of the water?

Siphon the majority of the remaining 10g water into the new tank after adding the substrate & decor?

I'll use new substrate. I've heard you can add a couple of hands full of old gravel in the tank.

Fill up the 20g with temperature-matched dechlorinator water.

Use the old filter in addition to the new one. Leave the old filter for a couple weeks.

After 2-3 weeks, the old filter and the old substrate can be removed.
 
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mattgirl

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ghostdawg said:
I'm ready to start moving everything from my 10g to my 20g long tank. Since I'm going to use the same tank stand, I need to move the 10g first and add the 20gl on top and put the 10 on the bottom of the stand. These are some steps I think I could do to start. All suggestions/advice is accepted!

To move the old tank, drain about 80% of the water?

Siphon the majority of the remaining 10g water into the new tank after adding the substrate & decor?

I'll use new substrate. I've heard you can add a couple of hands full of old gravel in the tank.

Fill up the 20g with temperature-matched dechlorinator water.

Use the old filter in addition to the new one. Leave the old filter for a couple weeks.

After 2-3 weeks, the old filter and the old substrate can be removed.
One thing I would do. You may be planning on doing it already but I would drain the water from the 10 gallon into buckets and pour it in the 20 once it is in place. There is little to no bacteria in the water but it is the water both your fish and the bacteria are used to. By using most of it and then filling the tank with fresh dechlorinated water your fish will just feel like they have had a 50 or 60% water change.
 

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Great. So I would need to put the fish in a temp bucket also? Another question. I'm planning on doing the switch Saturday. Should I do a WC & vac now or leave it alone altogether?
 
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mattgirl

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ghostdawg said:
Great. So I would need to put the fish in a temp bucket also? Another question. I'm planning on doing the switch Saturday. Should I do a WC & vac now or leave it alone altogether?
I would put the fish in a bucket with water from their tank. You may want to consider running the filter or at least an airstone in the bucket. The water change depends on how long it has been since your last one. If you have done one recently just wait until you make the move.
 

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mattgirl said:
The water change depends on how long it has been since your last one. If you have done one recently just wait until you make the move.
Interesting. My last change was on the 12th. Here in the midwest, its getting hot & humid and evaporation has started. Should I change, top off or leave it until Sat.?
 
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mattgirl

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ghostdawg said:
Interesting. My last change was on the 12th. Here in the midwest, its getting hot & humid and evaporation has started. Should I change, top off or leave it until Sat.?
Totally up to you and kinda depends on how heavily stocked your tank is. If nitrates are low a top off may be all you need to do.
 
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mattgirl

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ghostdawg said:
Great. So I would need to put the fish in a temp bucket also? Another question. I'm planning on doing the switch Saturday. Should I do a WC & vac now or leave it alone altogether?
How did your switchover go? Hope all your water pets handled the move well and are now comfortable in their bigger home. :)
 

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