# "Instant" cycle of new tank?



## andy531 (Feb 25, 2015)

Hi folks,

Hoping someone has some advice for me. I currently have a 33 gallon tank with 10 mbuna in it. I'm looking at getting a 70 gallon tank to replace it so the fish have more room and I can maybe add a few more. The thing is, the 70 gallon needs to go where the 33 gallon is currently.

To do this, I'm thinking about taking the fish out and temporarily putting them in a cheap-o 15 gallon with an air pump, then emptying the old tank & moving it out of the way.

If I then set up the new tank using the gravel, rocks and filter media from the old tank, (plus some additional new gravel etc. for the new, bigger tank, and maybe even a dozen gallons of the old tank water), how long until that new tank would be safe for the fish?

Thanks!


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## TripleW (Apr 3, 2012)

I would think that you should be ok.

One thing that you may want to keep in your mind....I had a 20 gallon Long tank that was established.....It had a gravel type substrate in it....I decided that I wanted to put sand in it...I basically capped the gravel with sand...my tank went through a mini cycle right after I did this...the only thing that I can think of is that I covered so much of the gravel that the BB on it could not get to the water column. It wasn't a big deal because I caught it and it corrected itself in about a week. May be something to keep in mind when putting in the new substrate.

Also keep in mind that when messing with the balance of a tank things can go wrong no matter how much prep...always have a backup plan.


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## andy531 (Feb 25, 2015)

Thanks for the reply.

So you just added sand to your already established tank and it caused a spike?


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## andy531 (Feb 25, 2015)

Like you didn't change tanks, filter media or anything at the same time?


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## Cyphound (Oct 20, 2014)

I would change out to sand. Less mess and you will love how the fish act with it. When I changed out my gravel to sand a few years ago in my oldest tank I bought a large storage container with lid and used that. Threw a bunch of the rock in, half the tank water, and conditioned new water, the heater and filter. Ran it for 3 days that way. No problems. Don't fed the fish for a couple of day before and during the change. Rest the lid over it and open slightly a few hours a day so they keep there circadian rhythm. When I was finished I used the container for summer/winter clothing which my wife liked (bonus) and I now have an emergency tank if needed. As for the gravel put a bunch of the old gravel in a couple of Nylon socks and place on the new substrate for a while near some flow like filter intake or even better a power head.


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## andy531 (Feb 25, 2015)

Thanks for the reply cyphound. Yeah sand seems to be the way to go. You just used a Rubbermaid tub with a HOB and a heater? Makes sense. Just gotta figure out a way to keep my cats from harassing the fish...I'll need some kind of secure lid for it.


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## Cyphound (Oct 20, 2014)

Put my tank on the dining room table and the cats never even cared. make syphoning it out after easier


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## TripleW (Apr 3, 2012)

andy531 said:


> Thanks for the reply.
> 
> So you just added sand to your already established tank and it caused a spike?


Yeah all I did was add sand...it was very odd...it was not even that big of a spike if I remember correctly, but enough to get my attention.


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## Mcdaphnia (Dec 16, 2003)

TripleW said:


> andy531 said:
> 
> 
> > Thanks for the reply.
> ...


It's not that odd that adding sand to gravel would cause a spike. When you combine sand and gravel, the sand fills the spaces between the gravel pieces, blocking off the flow of water and oxygen to the nitrification (cycle) bacteria. The ammonia is blocked from reaching the bacteria, and the bacteria would not have enough oxygen to process it anyway. Mixing sand and gravel together creates an anaerobic zone.


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## DJRansome (Oct 29, 2005)

I just us 5G buckets when moving fish. You can even put your heaters and HOB filters right on the buckets.


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## nodima (Oct 3, 2002)

Many times I've set up tanks in the manner you describe - as long as you use the existing filter media and don't add a ton of new fish at the same time, the tank will basically be instantly cycled. This assumes you can match temperatures and water parameters of the old tank which should not be a problem in the same house.

As DJRansome does, I put fish in 5 gal buckets, and do the move. For tanks of that size, it should not take more than a couple of hours, tops. Plan out all your moves ahead of time, and do anything you can to make the actual process smooth. Make sure your new substrate is well washed before you start moving fish etc. Another good trick if you are going to get a new filter for the 70 is to get that a month earlier than the tank, add media to it, and run it on the 33 to seed it.

Good luck!


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## co4nd2 (May 17, 2015)

I've moved and switched tanks a lot, one thing I always do is use as much of the original water as possible, so as not to shock your bacteria, and make sure they have enough food for it (fish waste, ammonia, nitrite) right away. always use as much filter media as possible and disturb it as little as possible.

For the five gallon buckets get lids and put some holes in them for air, fish stressed sometimes jump. plus the darker the bucket the less stressed they'll be, use some stress coat in the buckets. I've also used coolers, though the wife usually gets mad at me for that.


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## Mcdaphnia (Dec 16, 2003)

I don't think that new water is going to shock, surprise, or otherwise or otherwise affect bacteria. These are thigmotrophic bacteria, so they are somewhat protected from the water unless they happen to be right at the outer layer of their colony. Other than for temperature and maybe pH, the old water is much better put to use watering houseplants or the lawn. From reading and talking with much older fish keepers, I think there was once a sizable minority of aquarists who believed in the value of old water and no matter how yellow or murky it became, they saved every drop of it. There were even tools that would suck up fish droppings into a bag that then strained out the water and returned it to the tank. I always thought of these as aquarium artifacts from the 1920's but amazingly they are still being merchandized. http://www.amazon.com/Super-Battery-Pow ... B0002565N4


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## DJRansome (Oct 29, 2005)

As long as your old water is clean (10ppm to 20ppm nitrates) I would use 100% new water. You will have to match temp and pH/KH as Mcdaphnia states.


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## Fishnut71 (Dec 7, 2014)

Mcdaphnia said:


> There were even tools that would suck up fish droppings into a bag that then strained out the water and returned it to the tank. I always thought of these as aquarium artifacts from the 1920's but amazingly they are still being merchandized. http://www.amazon.com/Super-Battery-Pow ... B0002565N4


I actually still use this vac on my smaller tanks, not to save old water, but because I make my own diy water changer rigs and just need this vac to suck up poo. And to clarify that I don't believe in "old water", I do a 50% wc every 4 days on all my tanks.


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## co4nd2 (May 17, 2015)

Mcdaphnia said:


> I don't think that new water is going to shock, surprise, or otherwise or otherwise affect bacteria. These are thigmotrophic bacteria, so they are somewhat protected from the water unless they happen to be right at the outer layer of their colony. Other than for temperature and maybe pH, the old water is much better put to use watering houseplants or the lawn. From reading and talking with much older fish keepers, I think there was once a sizable minority of aquarists who believed in the value of old water and no matter how yellow or murky it became, they saved every drop of it. There were even tools that would suck up fish droppings into a bag that then strained out the water and returned it to the tank. I always thought of these as aquarium artifacts from the 1920's but amazingly they are still being merchandized. http://www.amazon.com/Super-Battery-Pow ... B0002565N4


I don't believe in saving old water as a practice but when moving or upsizing a tank it has always worked for me. I do advocate large weekly water changes on established tanks.


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