# Advice on cycling a tank with established filters



## SophieThomas (May 12, 2010)

I will be setting up the new 125G tomorrow and will be putting two filters on it. An eheim that has been running on my 55G for nearly two years and then another that was running on the 125G for some time but has been sitting dry for a few weeks. I will also be putting rocks and driftwood straight into the 125G out of my cycled 55G. 

I was going to give it a week to run before I started moving fish over into it. Some fish will be from my 55G and others will be new. 

This to me seems like I'm just doing a 100% water change and adding on a new filter but I have had it mentioned to me that it doesn't matter, I should still cycle the tank for a few weeks. What are some other opinions??


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## 2wheelsx2 (Apr 21, 2010)

You're a bit off on the "cycling". When you are cycling a tank, you're not really cycling a tank, but the filters. So in your case, the filter from the 55 is fully cycled. The other filter from the 125 that has been dry is not cycled and will not help you. You should clean that one out completely as the bio bed is dead. And do not run the filter for a week before adding fish, as the lack of ammonia will cause most of the bio bed to die back.

The sequence of events when using a cycled filter is this:

Add substrate and water, plus dechlorinator. Bring the tank up to tank. Add cycled filter. Add filter. The filter and the fish should be be more than 24 hours apart or you will get a mini cycle.

With the filter from the 55 in the 125, you just have to ensure you don't overload the tank since it's bioload will be suitable for a 55 (unless the 55 was severely overstocked). The 55 filter will see your other filter. Adding wood/plants/substrate from a running tank will greatly help also, as they will all have bacteria on them.


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## taureandragon76 (Apr 21, 2010)

Another thing you could consider to is take some of the media from the cycled filter and swap some with the one that is not cycled, not all just some. It will help establish bio in the uncycled filter. Or you could squeeze out your cycled sponges directly into the tank, this will also help establish bio in the uncycled filter. I have heard you can add fish right away doing this, I never have. I usually give it a day or two, in emergency cases(tank breaking) I would do it without any worries.


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## SophieThomas (May 12, 2010)

To be a little clearer, I have danios that I cycle with so it wouldn't be strictly fishless. There will be 13 of them in the tank. Man, I should really double check my info before I click post. The fish that will not be going in that I was referring to are the fish from my 55G which, now that Max is in there, is currently overstocked by quite a lot. So the eheim is running alongside an AC110 to help combat the increased bioload.

My question more surrounds how healthy it is to then, a week later, put in a bunch of gouramis, cories, cardinal tetras, otos, etc. I thought this would be completely fine considering the cycled eheim and driftwood, etc.

In regards to overloading the tank, do you mean don't stock the tank suddenly with significantly more fish than I had in the 55G? The only fish that will be added later are 5 1.5-2" clown loaches but at the same time, Max (the pleco) will not be moved over as he is staying in the 55G so I figure that will even it out a bit.

The dry filter has been completely cleaned and I was going to add a sponge from another cycled canister filter I have running. Like I said above, driftwood and rocks will be going into the 125G tomorrow. There is also a large onion plant as well. 

The guy I spoke to about this seemed certain I was doing something very wrong here...


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## taureandragon76 (Apr 21, 2010)

Sounds to me like your doing nothing wrong. Like you said essentially it's basically a large water change.


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## target (Apr 21, 2010)

If you are transferring the filter from an overstocked 55 to the new 125 I would add the new fish right away. It will have a big bio bed already established.

If you take the filter from the overstocked 55 and put it in the understocked 125 you will lose a lot of the bio bed as there won't be enough ammonia to feed it.

IMO I would add all the fish you want when you transfer the filter. Then just watch your water for a few days and golden.

When I combine my 2 46's into the one 90 I will be taking the media from the filters in both tanks and putting it into the canister on the 90. Then fill the tank, add dechlorinator, the fish and it will be finished.


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## SophieThomas (May 12, 2010)

Exactly!! lol I was so annoyed after the conversation because we have had this move set up for weeks. We are very excited to finally get this 125G up and running (which has been in the making for a few months now) and I was quite comfortable that we had considered everything we needed to. Blarg, lol.


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## 2wheelsx2 (Apr 21, 2010)

As the others have said, you're ok. As long as the water has similar chemistry and close enough temperature and is dechlorinator, slap the new filter in there and put the fish in right away. Waiting just gives time for the bacteria to die back. Having 13 danios in the 125 will mean the bio bed will die back to support 13 danios, unless you're going to add raw ammonia to feed the bio bed.


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## donjuan_corn (May 6, 2010)

If you are using the same cycled filters you should be fine. It's all good!


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## Peterchow (Apr 21, 2010)

SophieThomas said:


> I will be setting up the new 125G tomorrow and will be putting two filters on it. An eheim that has been running on my 55G for nearly two years and then another that was running on the 125G for some time but has been sitting dry for a few weeks. I will also be putting rocks and driftwood straight into the 125G out of my cycled 55G.
> 
> I was going to give it a week to run before I started moving fish over into it. Some fish will be from my 55G and others will be new.
> 
> This to me seems like I'm just doing a 100% water change and adding on a new filter but I have had it mentioned to me that it doesn't matter, I should still cycle the tank for a few weeks. What are some other opinions??


Yes, let the water sits for a week minimum before moving your fish in there. Nowadays city water has very strong cholrine, and if you move your fish too soon, you will have problems.


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## target (Apr 21, 2010)

Peterchow said:


> Yes, let the water sits for a week minimum before moving your fish in there. Nowadays city water has very strong cholrine, and if you move your fish too soon, you will have problems.


Isn't that what dechlorinator is for? Add to the water, and the chlorine is neutralized. I use straight tap water into my tanks. Add some Prime first, then the water flows right in. Never had an issue.


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## 2wheelsx2 (Apr 21, 2010)

I guess since one of the filters is not cycled, it can be naturally dechlorinated with running the second canister for a week. That way, you can clear any cloudiness and troubleshoot any issues with the setup and then just add the cycled filter and the fish in the second week.


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## SeaHorse_Fanatic (Apr 22, 2010)

No need to wait, IME. I have set up many tanks by simply taking one of my spare filters off an existing tank & placing it on the new one. Instant cycle. Even faster if you're doing it at home and not moving the filter to another house.

Anthony


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## Peterchow (Apr 21, 2010)

target said:


> Isn't that what dechlorinator is for? Add to the water, and the chlorine is neutralized. I use straight tap water into my tanks. Add some Prime first, then the water flows right in. Never had an issue.


If you are setting up a small tank, the dechlorinator will work. But if the new tank is over 100 gal + and all water is from the tap, even heavy dosage of dechlorinator + prime will not guarantee the water is safe 100%.

I am not here to argue. When I set up my 210 gal monster tank a few months ago, I was using 50% aging water + heavy dosage of water conditioner + salt, with all used filters. I waited for a few hours and transferred all fish into the new tank. ALL FISH DIED within a week.


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## SophieThomas (May 12, 2010)

Peterchow said:


> Yes, let the water sits for a week minimum before moving your fish in there. Nowadays city water has very strong cholrine, and if you move your fish too soon, you will have problems.


The chloramines in my water are very low. In fact, my water comes out my tap at the right pH and GH as well  I also use Nutrafin Aqua plus with each water change to counteract any chloramines present. I haven't had any problems yet but I guess we will see.

Ordinarily, if I was not using dechlorinator or was drinking treated water myself (like when I backpack/hike) I would let it sit to let it evaporate out.


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## SophieThomas (May 12, 2010)

Peterchow said:


> If you are setting up a small tank, the dechlorinator will work. But if the new tank is over 100 gal + and all water is from the tap, even heavy dosage of dechlorinator + prime will not guarantee the water is safe 100%.
> 
> I am not here to argue. When I set up my 210 gal monster tank a few months ago, I was using 50% aging water + heavy dosage of water conditioner + salt, with all used filters. I waited for a few hours and transferred all fish into the new tank. ALL FISH DIED within a week.


I'm certainly not wanting to argue or anything here either but what led you to the conclusion that it was the chloramines? Living in Abbotsford (which has an independent water source from the cities around it) it had never really crossed my mind as a real threat.


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## gklaw (May 31, 2010)

I run all my water through canister carbon filter - I drink from that as well. Done 50% water change for my discus with that. Never had a problem - yet 

To be safe. When I set up new tank, I do a major water change from another tank and use the old water for the new tank. Then use hald the media from another filter to the new filter. Water through carbon and whatever fish goes in right the way. No death yet.


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## target (Apr 21, 2010)

Peterchow said:


> If you are setting up a small tank, the dechlorinator will work. But if the new tank is over 100 gal + and all water is from the tap, even heavy dosage of dechlorinator + prime will not guarantee the water is safe 100%.
> 
> I am not here to argue. When I set up my 210 gal monster tank a few months ago, I was using 50% aging water + heavy dosage of water conditioner + salt, with all used filters. I waited for a few hours and transferred all fish into the new tank. ALL FISH DIED within a week.


Sorry if that sounded argumentative. It wasn't intended to be. When setting up my tanks I just used tap water and 2x the dosage of prime to be safe. Granted, they were only 46g tanks, but I never had any issue. Your experience isn't a nice one to go through so thanks for sharing.


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## donjuan_corn (May 6, 2010)

Target, i've never had a problem either with the tap water and some prime. Moved the 90 gallon tank when I moved, ran the filter for 6 hours with the new water and then added the fish when the temp was right.


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## Fishman21 (Apr 26, 2010)

3 weeks ago I experienced the same challenge - set up an unused 125G in a new house we were moving to in Maple Ridge from Coquitlam. I added an existing operational eheim canister, and 2 brand new AC500's. the first 3 or 4 days showed hazy water warning of bacterial spike so I added another AC300 (Very dirty! - I actually rinsed it all into the tank) and water was bright and clear within a day or 2.

I continued let it run (With no fish) for a little longer and then brought the fish across after a total of about 10 days from setup. 

Stock:
3 large 9" Uaru - they are quite sensitive and like water conditions similar to Discuss so I was nervous with the transition
3 large Angels & a BN Pleco 

No problems, in fact the Uaru spawned 3 days ago - they just thought it was another water change and got excited

i think you have done enough to be safe


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