Using existing filter media to cycle new tank?

[SnifflySnail]

I have a 5 gallon that I’ve finally cycled. I’ve been considering upgrading to a 20 gallon & id like to keep my 5 gallon going.

if I purchased a second sponge filter the same as the first, could I cut the sponge in half and replace half of it with new, then put the other half in the new tank with half new? Would that instantly cycle the tank or would it still take some time?

 

[StarGirl]

How long has the tank been cycled? If just recently it may take some time still. It would depend on how many fish you add. If you had a betta in each tank it may be ok. You would have to add fish really slowly to allow the sponge to catch up or it will cause a spike.

How would you cut a sponge filter in half? I think the bubbles would leak through the cracks where its cut. You could also put the second sponge in the 5g to seed for a month or so. What fish are in the 5g?

 

[Fishfur]

I have a 5 gallon that I’ve finally cycled. I’ve been considering upgrading to a 20 gallon & id like to keep my 5 gallon going.

if I purchased a second sponge filter the same as the first, could I cut the sponge in half and replace half of it with new, then put the other half in the new tank with half new? Would that instantly cycle the tank or would it still take some time?

There is another way to seed the new tank and you won’t have to cut up sponges. Take the sponge from the 5G and give it a thorough rinsing in as little tank water as possible. Wring it and beat it up a bit, the idea is to knock off some of the bacteria into the rinse water. The ones inside the sponge stay put and just some of the exterior ones get knocked off so it won’t spoil the cycle you have now in the 5.

Then pour the dirty rinse water into the new filter, or soak the new sponge in it and try to soak up as much of it as possible and pour the rest in the tank. You can siphon out any grungy stuff that ends up on the bottom later on. It may cloud the water a bit, this is to be expected but it’ll clear up fine given a day or less to run the filter.

This usually gets you enough bacteria that you can add one small fish, at most just one, the same or the next day or else use some actual ammonia and it’ll be a stable cycle in almost no time - a few days is usually all it takes though it will take longer than that to build up enough bacteria to support a stock of fish.

 

[RayClem]

While seeding your new filter with media from your old filter will speed up the cycling process, there is no such thing a instant cycling. This is even more the case when your are upgrading to a larger tank. A 20 gallon tank will require approximately 4 times the beneficial bacteria as the 5 gallon tank. For a tank to be considered fully cycled, not only does the filter media need to build up colonies of microorganisms, but the substrate and tank walls have to grow their share as well.

 

[SnifflySnail]

While seeding your new filter with media from your old filter will speed up the cycling process, there is no such thing an instant cycling. This is even more the case when your are upgrading to a larger tank. A 20 gallon tank will require approximately 4 times the beneficial bacteria as the 5 gallon tank. For a tank to be considered fully cycled, not only does the filter media need to build up colonies of microorganisms, but the substrate and tank walls have to grow their share as well.

Good to know. Would adding some of the dirty substrate from the 5 gallon help things along too?

There is another way to seed the new tank and you won’t have to cut up sponges. Take the sponge from the 5G and give it a thorough rinsing in as little tank water as possible. Wring it and beat it up a bit, the idea is to knock off some of the bacteria into the rinse water. The ones inside the sponge stay put and just some of the exterior ones get knocked off so it won’t spoil the cycle you have now in the 5.

Then pour the dirty rinse water into the new filter, or soak the new sponge in it and try to soak up as much of it as possible and pour the rest in the tank. You can siphon out any grungy stuff that ends up on the bottom later on. It may cloud the water a bit, this is to be expected but it’ll clear up fine given a day or less to run the filter.

This usually gets you enough bacteria that you can add one small fish, at most just one, the same or the next day or else use some actual ammonia and it’ll be a stable cycle in almost no time - a few days is usually all it takes though it will take longer than that to build up enough bacteria to support a stock of fish.

Fantastic! Super happy to know I won’t have to mutilate any sponges for this

 

[fishywoo]

Good to know. Would adding some of the dirty substrate from the 5 gallon help things along too?

Fantastic! Super happy to know I won’t have to mutilate any sponges for this

Adding the established substrate will definitely help the beneficial bacteria colonize in the new substrate. ^_^

 

[RayClem]

Substrate from an established tank is another way of seeding the nitrogen cycle.

 

[SparkyJones]

You can move the fish and cycled filter to the 20g from your 5g and run the old and new filter parallel for a month and let the old filter's cycle run the 20g while it establishes the cycle in the new filter, after a month the old filter can then be put back in the 5g. And filled and both are good to go. This gets you the additional space immediately although you can't really keep both tanks at the same time immediately.

Safest way I know to get both filters cycled and up and running without risks to fish.

I use some sponge filters. I have a 10g for quarantine and an extra sponge running on another tank, when I don't need the10g It's drained cleaned and dried, and the filter moved to another tank to keep its cycle.
When I need the quarantine, I fill the 10g, dechlorinate, then move the filter over again and it's good to go immediately.

If you have to have both running at the same time and don't want either shut down, you'll need ammonia for the new tank, moving substrate or sponge squeezing will only get you so far, maybe a small percentage of the colony then they need food (ammonia and nitrite) to multiply. That way functions like a bacteria in a bottle. It will give you some of the colony as a starter, but not enough to run the tank with fish it will speed cycle though. That's called "seeding".

What I would do, move the sponge from the 5g to the 20g and the fish, and let the cycle colonize over to the new sponge for a month or so while the old sponge does the work, then move it back and you'll have both running and can move fish around or buy new fish to stock either.

The 5g can be completely cleaned and dried out for that time, it doesn't matter. The cycle is in the sponge filter and it's just giving it time for the bacteria colony to split and colonize from the old sponge to the new sponge.

This way you get to use the larger tank right away. If the filter can handle the fish load on the 5 gallon, it will handle the same fish load on a 20 gallon also.
You can also move the filter back after 15 days and test the 20g to see what it's doing and if its done. the new filter should cycle quickly since it's starting with all of the bacteria from the 5g tanks filter, millions of bacteria all multiplying, it's not like your first cycle where 1 becomes 2 then 2 becomes 4 and takes forever to get to 1 million becomes 2 million ect. The colony will size up quick starting with a big colony and take over the new sponge quickly.

And if you think you may want to go to a 3rd tank at some Point, run an extra sponge filter on the 20g, then you'll have one ready to move on day 1 if you do get a 3rd tank. Nothing wrong with more filtration anyways.