Can You Save Cycled Filter Media?

[NewTankGuy]

I just moved from a 29-gal tank to a 75, and have been using my old filter in my new tank to help ease the transition.  Now my question is, in about a week, when I no longer am using the filter, and its media, for my new larger tank, is there a way to save, or preserve the cycled media so that if I decide to use my 29-gal again, I already have a filter that’s cycled? Or is there no way to save this for a few months, and just toss it and start all over if I do want to get a second tank up and going?

 

[star4]

If you can get the media from the small filter into the large one this is one way to save it. I have various small filters for emergencies, I keep the media for them in my canister filters.

 

[attibones]

What I would do is set up a large filter for the 75 gallon and run the smaller filter alongside it. Additional filtration is never a bad thing and all your media would be safe. Or you could load all the media into a stocking or something similar and load it into the 75 gallon filter. The problem with this is that you would remove media from the 75 gallon when you set up the 29 gallon. You could also put the stocking in the tank I think.

 

[TwoTankAmin]

There really is no cost effective way for us to save smaller amounts of cycled media for months and have it be useful.  I run a biofarm tank but it has anywhere from 5 -8 filters running at any time and this is on a 20 gal tank. I feed the tank ammonium chloride and crushed coral in a bag. But if you callculate all my costs they only make sense because I use these filters and put others back in regularly. For one smaller filter it would not make much sense. Its cheaper to buy a bottle of viable bacteria when you restart the tank.

 

[Alasse]

Just leave the old filter running on the 75gal

 

[TwoTankAmin]

The amount of bacteria in any tank results from the amount of ammonia available. No matter how much bio-media one puts into the tank the total amount of bacteria on it does not change. What makes the amount of bacteria increase or decrease over time is the amount of ammonia being made available.
 
So when you move over the old filter to the new tank and continued to cycle the new tank, the total amount of new bacteria developed will be less because you have put some into the tank in the old filter.
 
Down the road if you remove the old filter or the old filter media, you will be removing that amount of bacteria from the 75. To that extent it will cause a mini-cycle in that tank. But there is another caveat. Over time the bacteria in any tank may remain fairly constant, but its location may not. So there is no was one can assume that the amount of bacteria in the old filter when it was moved is the same three months later. It could be less or more.
 
My assumption was you wished to preserve the bacteria already in the filter so you might use it at a later time if the 29 were wanted again. In essence you want all the bacteria in the filter from the 29 preserved apart form all the bacteria in the 75 keeping it cycled. What folks suggest would not do this.
 
What they suggest is equivalent to never having had the 29, having multiple filters on the 75 and then removing one, or its media, to start up a new 29.

 

[Alasse]

I have spare filters running in my tanks and when removed they don't cause any mini cycle *shrugs*

 

[TwoTankAmin]

That's great Al. I am happy for you. Many people will not get your results. So I would still advise anybody moving over media or filters etc. from an established tank to a new one to monitor ammonia and nitrite over the next 24 hours, at least, to be safe. At best one will have wasted a bit of time and a couple of tests, at worst they might harm or even lose fish.
 
And what you wrote above is a bit misleading in its simplicity. You give no info on the size and stocking in the donor tank nor the receiving tank. You say nothing about how many or what size filters are involved or what mix of media is in them. You make no mention of the presence of plants. All of this becomes relevant in each instance. What you have done and what somebody else will do are tank and situation specific and not identical experiences.
 
The thing is none of us know exactly where all the bacteria in any of our tanks might be living. How do we even know when have two identical filters running that each will contain the same amount of bacteria? What we do know is if a tank is fully cycled or not. Either it handles the nitrogenous wastes or it doesn't. So we also have no idea if we remove things that are likely to host bacteria exactly how much bacteria we are removing. Miss a water change or two and filter media clogs and some bacteria dies. The tank doesn't spike ammonia, instead the bacteria reproduce elsewhere in the tank to compensate. As long as they get what they need, they don't really care where they are- filter, gravel, decor or on plants.
 
NTG- just because you say are no longer using the filter does not mean the tank doesn't use the bacteria in it. It isn't the filter that matters, its the bacteria in the media. So even if you leave it on the tank for the next 3 months and then move it back to a reset up 29, there is no way to know how much bacteria is in that filter compared to how much was there when you move it onto the 75. And if you pull it off in about a week, please test the tank over the next day or two to insure things are OK.

 

[Alasse]

Various tank sizes, various stocking levels, and various filter sizes.
 
By all means test if you feel you need to....I certainly have (I don't so much now) and have never had any issues doing it that way and why I mentioned it