When moving fishes to a new tank, can I simply re-use all water of the old tank?

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kachibi

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I am raising some koi fishes (freshwater ones) and I will have a new tank very soon. So, I am going to move the fishes from the old tank to the new tank. The sizes of the tanks are similar.

So, I know the first thing to do is to fill up the new tank with new, salty water and leave the water there for at least one day. This step is to ensure the tank does not leak and to sanitize the tank ( the use of salt to eliminate toxic substances of the new materials like the glass and the glass glue).

So, after this 1 day, I withdraw all salty water from the new tank. I guess some people may then fill up the new tank with new water (and perhaps mix it with some water from the old tank), and then start the series of letting the air pump and the filter run, adding dechlorinator, cycling the tank, etc. for few days, before putting fishes in.

Assume that I will re-use all the equipments (the filter, the air pump, etc.) in the new tank, no slate, wood or plants. And now I decide to simply relocate all the old water to the new tank. And my old water is safe (which is cycled in the old tank, and the fishes are alright with it). So basically the difference is just the tanks. Can I skip the "pouring in new water then start the series of running the air pump, the filter, dechlorinating, cycling, etc." hassle in the new tank before putting the fishes into it?
 

SanDiegoRedneck

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kachibi said:
I am raising some koi fishes (freshwater ones) and I will have a new tank very soon. So, I am going to move the fishes from the old tank to the new tank. The sizes of the tanks are similar.

So, I know the first thing to do is to fill up the new tank with new, salty water and leave the water there for at least one day. This step is to ensure the tank does not leak and to sanitize the tank ( the use of salt to eliminate toxic substances of the new materials like the glass and the glass glue).

So, after this 1 day, I withdraw all salty water from the new tank. I guess some people may then fill up the new tank with new water (and perhaps mix it with some water from the old tank), and then start the series of letting the air pump and the filter run, adding dechlorinator, cycling the tank, etc. for few days, before putting fishes in.

Assume that I will re-use all the equipments (the filter, the air pump, etc.) in the new tank, no slate, wood or plants. And now I decide to simply relocate all the old water to the new tank. And my old water is safe (which is cycled in the old tank, and the fishes are alright with it). So basically the difference is just the tanks. Can I skip the "pouring in new water then start the series of running the air pump, the filter, dechlorinating, cycling, etc." hassle in the new tank before putting the fishes into it?
So almost NO benificial bacteria is in the water colomn. (Just old waste you dont want) It's all in filter mostly but also on hard surfaces like plants and decorations. If you move the filter and decorations/ plants you should instantly cycle. Never move water no BB there.
 

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SanDiegoRedneck said:
So almost NO benificial bacteria is in the water colomn. (Just old waste you dont want) It's all in filter mostly but also on hard surfaces like plants and decorations. If you move the filter and decorations/ plants you should instantly cycle. Never move water no BB there.
I agree. I’ve used tank water in an emergency (filling up a tank while the other leaked) but that’s more of a time issue. So if you have plenty of time I’d say just start with new clean water.
 

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Keep the power filter running while you transfer the old substrate to the new tank. Try not to stir up the bio gunk. An almost impossible task.
Next, toss the filter media into the current tank, keeping it wet in old tank water.
Begin dumping the old tank water into the new tank. Transfer the fish when the new tank is half full.
Once the new tank is completely full, hook up the power filter. Reinsert the wet filter media & prime it with old tank water.
That should provide the best shot for an instant cycle.
 
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kachibi

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I have a doubt: if I move the old water from the old tank to the new tank in 1 day, and you know the fishes were originally alright with the old water just before the very process, does that make a significant difference from using all new water?

Provided that the old water is not really so old--1-2 days old (I mean the old water will have a regular 1/3 tank water change in the old tank 1-2 days before the relocation). I guess the relocation of such not really old water will not cause serious issues when it hits the new tank?
 

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kachibi said:
I have a doubt: if I move the old water from the old tank to the new tank in 1 day, and you know the fishes were originally alright with the old water just before the very process, does that make a significant difference from using all new water?

Provided that the old water is not really so old--1-2 days old (I mean the old water will have a regular 1/3 tank water change in the old tank 1-2 days before the relocation). I guess the relocation of such not really old water will not cause serious issues when it hits the new tank?
Why not use fresh water? Even after a few days nitrates build up? The water column has no BB and harmful waste. I dont see why you would reuse. Everytime I start a new tank or upgrade I use fresh water

But ultimately up to you.

Good luck
 
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kachibi

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SanDiegoRedneck
The reason why I would avoid using new water is that I have to do all those cycling things for the water (turn on the air pump, turn on the filter, add in treatments, and let the new water cycle without fishes for few days...), in this way I would use a bucket the hold the fishes. The thing is the length of time. The longer the time, the more chance the fishes will jump out and the more time the equipment and tools take up space in our dining room.

My room's geography does not allow cycling in the new tank while keeping the fishes in the old tank. We don't have such space. The fishes must be relocated to a bucket or another type of container. So if I have to use new water and do those cycling things, the fishes will be in the bucket/ other container for the same period of time.

If I just pour the old water into the new tank--which means no cycling is needed, things will be much easier. Once I pour all the old water into it, I then move the fishes from the bucket into the new tank quickly, without letting them wait in the bucket for few days (to wait for cycling in the new tank).
 

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kachibi said:
SanDiegoRedneck
The reason why I would avoid using new water is that I have to do all those cycling things for the water (turn on the air pump, turn on the filter, add in treatments, and let the new water cycle without fishes for few days...), in this way I would use a bucket the hold the fishes. The thing is the length of time. The longer the time, the more chance the fishes will jump out and the more time the equipment and tools take up space in our dining room.

My room's geography does not allow cycling in the new tank while keeping the fishes in the old tank. We don't have such space. The fishes must be relocated to a bucket or another type of container. So if I have to use new water and do those cycling things, the fishes will be in the bucket/ other container for the same period of time.

If I just pour the old water into the new tank--which means no cycling is needed, things will be much easier. Once I pour all the old water into it, I then move the fishes from the bucket into the new tank quickly, without letting them wait in the bucket for few days (to wait for cycling in the new tank).
I think you are misunderstanding. There is NO benificial bacteria in water column. If you move filter to new tank it will instantly cycle new water.
I've instantly cycled 5 tanks recently. Reused 0 old water

But up to you.
Good luck.
 

A201

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There is virtually no BB in the old water column, but nitrates should be present. Nitrates hold no value in relation to the BB present in the old filter media, but will help sustain with new or transplanted foliage.
 
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kachibi

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Thanks for all:happy:. I think I understand what you guys mean now: I can simply use all new water in the new tank immediately and safely, cause the old filter will do the cycling things for me--and thus no waiting is needed. I think this is what you guys want to say.

By the way, a side question: if existing water holds not much value, why people recommend only 1/3 water change, instead of complete water change of a tank, as long as I add in dechlorinator? Why must I keep 2/3 old water if they are bad?
 
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SanDiegoRedneck

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kachibi said:
Thanks for all:happy:. I think I understand what you guys mean now: I can simply use all new water in the new tank immediately and safely, cause the old filter will do the cycling things for me--and thus no waiting is needed. I think this is what you guys want to say.

By the way, a side question: if existing water holds not much value, why people recommend only 1/3 water change, instead of complete water change of a tank, as long as I add in dechlorinator? Why must I keep 2/3 old water if they are bad?
Because of stress to fish. A big water change puts some stress. So weekly not recommended. 15 to 40 percent depending on tank can keep nitrates in check while not weekly having big ph or TDs change.

Commercial breeders and lots of fish stores DO change 100% of water daily or more than once a day. But they have recycling systems that ensure that the replaced water is exactly the same water perameters.
 
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kachibi

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Then in my case, using all new water in the new tank will not cause stress (like what you say-ph/TD) to my fishes?
 
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SanDiegoRedneck

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kachibi said:
Then in my case, using all new water in the new tank will not cause stress (like what you say-ph/TD) to my fishes?
It will slightly. But if you use tap already and keep up on water changes your tank water should be close.

But as A201 Said they do reuse some water in new tank move. Both totally acceptable, I just wanted you to understand your BB is not in water. But there are as A201 said benefits to using some old water but I feel there are benefits of not.

Main thing is that you have cycled filter, regardless of method used this is the key part
 
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I am trying to understand the koi fish thing here. What size tank are these fish going to be kept in. It is my understanding these fish get huge, way to big for home aquariums. Maybe your talking about an outside pond or something similar.
 
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mattgirl

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If I were doing this I would add half the water in the old tank to the new one and then finish filling with fresh dechlorinated water. As others have already said, the bacteria isn't free floating in the water. It is growing on your filter media and all the surfaces in the tank.

The reason I suggest you use half the water in the old tank is because it is the water your fish and the bacteria are used to. By using half old tank water and half fresh water both fish and bacteria will just feel like they have gotten a 50% water change.

Be sure to keep decor and filter media wet while making the switch. You don't want to allow the surfaces to dry out. You will lose some bacteria since some lives on the glass but it shouldn't be enough to cause a problem. Just keep an eye on the parameters and do water changes should you get a spike in ammonia and/or nitrites.
 
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kachibi

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Thanks, I will either use all new tap water or at most 50% old water plus new tap water, as long as no cycling for more than 1 day is needed, as you guys say.

Utar No, I am just raising some middle-sized koi fishes, not those big ones. I have 5 koi fishes now in a 48" long tank. Since the tank is very old (10 years), we are afraid of leakage so we would like to have a new tank. By the way, this makes sense right?

By the way, you guys say the BB live in the filter and surfaces of the tank, that means on the glass windows and the bottom of the tank as well?
 
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mattgirl

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kachibi said:
Thanks, I will either use all new tap water or at most 50% old water plus new tap water, as long as no cycling for more than 1 day is needed, as you guys say.
Since you will have checked the new tank for leaks you can make the move all in one day. I was out of the hobby for about 6 years. When I set my tank back up I filled it and let it run for a couple of days just to make sure everything was working as it should. In your case you already know your filter is running as it should and the tank has already been leak tested so no need to wait to add the fish from the original tank.

Since the tank is very old (10 years), we are afraid of leakage so we would like to have a new tank. By the way, this makes sense right?
Have you been using this tank for its 10 years of life? I know some folks consider 10 years to be old but if a tank has been taken care of I don't consider it to be worn out just because it has a bit of age on it. I have had my 55 for close to 20 years. I know that it has been well taken care of for all this time. It has only been moved one time during all those years. It was empty and well supported during the move. It was dry, empty and covered well sitting on the original stand I put it on when I bought it during the 6 years I was out of the hobby.

By the way, you guys say the BB live in the filter and surfaces of the tank, that means on the glass windows and the bottom of the tank as well?
Yes, some bacteria lives on the glass. I don't think you will be leaving enough behind to cause a problem as long as you move everything else in this tank over to the new one, If that was your concern. The bacteria will quickly grow more to replace what has been left behind.
 
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kachibi

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Good, thank you for all.
 
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kachibi

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I come up with a question about the filter media.

So I have that kind of filter compartments that contain filter media as follow:

1598432836165.png


How should I handle the whole item while doing the transfer? One response above says I can put it in old water? So which items (the dirty sponges, the rings?) should I put in old water? Or the whole thing including the compartments? But it will be too big...
 
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SanDiegoRedneck

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kachibi said:
I come up with a question about the filter media.

So I have that kind of filter compartments that contain filter media as follow:

1598432836165.png


How should I handle the whole item while doing the transfer? One response above says I can put it in old water? So which items (the dirty sponges, the rings?) should I put in old water? Or the whole thing including the compartments? But it will be too big...
I didnt realize that's what you were working w. So yes just take sponges, rings ect out and put in bucket of tank water to keep wet. The plastic frame can dry out.
 
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kachibi

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The sponges are on the first tier and the rings are on the second tier. It means the dirty water will go through the sponges first and the sponges will keep the dirt (black matters) of the water, then the water go through the rings where BB are produced.

So basically I think the sponges are of no use because they just keep dirt? I can simply dispose them?
 
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SanDiegoRedneck

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kachibi said:
The sponges are on the first tier and the rings are on the second tier. It means the dirty water will go through the sponges first and the sponges will keep the dirt (black matters) of the water, then the water go through the rings where BB are produced.

So basically I think the sponges are of no use because they just keep dirt? I can simply dispose them?
No that is taking physical particles any chunks or maybe s string of plant out of water plus BB grows on it.
 
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mattgirl

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I am not sure you understand why we are telling you to handle your filter media the way we are. Most of your cycle (the bacteria) lives on the media in your filter. It lives on the sponge and on the other media. If it gets too dirty you can rinse it off in some of the water you have pulled from the tank. Your filter media is the one thing in your home that you don't want to keep spotlessly clean.

The sponge is doing what it is supposed to do. It is your mechanical filtration. It filters out big particles but while it is doing that it is also growing bacteria in all the pores. It needs to be cleaned out from time to time but shouldn't have to be replaced until it is literally falling apart. Just squeeze it in some water you have pulled from the tank or in some fresh dechlorinated water.

You need to occasionally rinse the bio-rings too but not as often as you do your sponge. Again rinse them of in water pulled from the tank.
 
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Flyfisha

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one hundred answers already but.
In my opinion.
When moving to a new tank use all the old water because. And only because. The temperature of the water is the same for the fish as they move. The parameters are the same for the fish as they move. The parameters are the same for the bacteria as they move. It’s stressful enough on on the fish as it is spending time in a bucket as they move to a new tank.

Do water changes the day before you move them , or the day after but not at the same time.
 
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kachibi

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Very good, all are understood!
 
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