Will cycling tank this way work?

HI guys, I am about to set up a 10 gallon planted betta tank. I already have a 30 gallon established tank that has been running for a few years. The 30 gal has a penguin HOB filter that has a filter cartridge, a biowheel, and a random sponge sheet I added in years ago (made for 5 gallon filter).

I was thinking I could buy the sponge filter I plan to use for the 10 gal and start it running in the 30 gal tank for a few weeks until it builds up bacteria.

Then set up the planted tank and transfer the sponge filter to it and the sponge sheet from the 30 gal just free floating in the water (I don’t really have anywhere else to put it). I thought I could also fill 50% of the 10 gal up with used water from my established tank. The rest of the tank will be filled up with new water. I also have bacteria quick start in a bottle I can use. Is this enough for an instant cycle? If not should I run the tank for a few weeks while adding fish food for ammonia?

 

Yes you can do that. However keep in mind bacteria grow on surfaces and don’t float in the water column. Taking water from the cycles tank to the new tank isn’t a bad idea it just won’t help with the cycling. Also the filter sheet from the other tank will need to be placed in the filter. Alternatively you can get some media or another filter sheet and start it in your already cycled tank To transfer it. Be careful not to take too much cycled filter media from the already running tank to the new tank or you could run into trouble in the established tank.

 

You need to have your tank water ALL moving over/through your BB. If your sponge is just floating in the tank, that won't really work. If its a sponge filter that's hooked up to an air line then yes, you can let that bob around the tank. But to me it sounds like you want to just drop a sponge in and let it float around. That won't work.

Also, taking water from a cycled tank won't do anything. Yes, SOME bacteria is present everywhere, but moving old tank water, substrate, plants, etc., won't "cycle" the tank. It might help kick start a BB colony, but that's it.

 

It's impossible to say for sure. You have several filters on the current tank, which is good, but you can't tell what percentage of the bioload is handled by which filter. You'll also have a clean tank with no biofilm on the sides, substrate, or decorations. Your plan will certainly provide a good bed of seed bacteria. You should test daily at first to confirm whether the transferred media is handling the bioload, and do water changes accordingly to keep ammonia and nitrite levels at 1 ppm or below.

The beneficial bacteria live on surfaces, not in the water column. Using water from the old tank won't affect your cycle.

I've never used bottled bacteria. It's a shortcut, doesn't work as advertised, messes with your test readings, and the results are wildly inconsistent.

 

You need to have your tank water ALL moving over/through your BB. If your sponge is just floating in the tank, that won't really work. If its a sponge filter that's hooked up to an air line then yes, you can let that bob around the tank. But to me it sounds like you want to just drop a sponge in and let it float around. That won't work.

Also, taking water from a cycled tank won't do anything. Yes, SOME bacteria is present everywhere, but moving old tank water, substrate, plants, etc., won't "cycle" the tank. It might help kick start a BB colony, but that's it.

Thanks for the reply, very helpful, I guess I will just leave the sponge sheet in the established tank. I don’t have anywhere to put it in the new tank, the only things that will be in there is the sponge filter, substrate, and plants. I will leave the tank running for a few weeks while doing water changes and adding the fish food. The betta I want is very expensive and I really want this to work out for the lil guy.

 

If your 30 gallon tank has a heavy bio-load meaning lots of fish, running the new sponge filter in there for at least a month should seed it well enough to pretty well instantly cycle the new tank as long as there are fewer fish in the new tank as there is in the tank you use to seed the filter. There should be enough bacteria on the sponge filter to handle the bio-load of the one fish.

I have done this numerous times over the years and have never had an instant cycle fail me. I never get an ammonia or nitrite spike and always start seeing nitrates within a few days.

If you would feel more comfortable testing it before getting your fish though. Run the sponge for a month in the cycled tank. Set up the new tank. If you are going to use fish food as your ammonia source put some in there before you move the seeded sponge over. Wait until you see an ammonia reading before you move the seeded sponge. The bacteria needs food. If the next day after moving the sponge the ammonia has gone back to zero you will know that the sponge will handle the bio-load of your Betta. Either put your betta in there at this point or continue feeding the bacteria with fish food.

 

Thanks for the reply, very helpful, I guess I will just leave the sponge sheet in the established tank. I don’t have anywhere to put it in the new tank, the only things that will be in there is the sponge filter, substrate, and plants. I will leave the tank running for a few weeks while doing water changes and adding the fish food. The betta I want is very expensive and I really want this to work out for the lil guy.

If all you're adding is a single Betta in a 10 gallon, I wouldnt even worry about it. They have such a tiny bioload it won't be a big deal. Just don't overfeed him, stay up on water changes and you'll be fine. I never cycle a tank before adding a single Betta.

 

Thanks for the reply, very helpful, I guess I will just leave the sponge sheet in the established tank. I don’t have anywhere to put it in the new tank, the only things that will be in there is the sponge filter, substrate, and plants. I will leave the tank running for a few weeks while doing water changes and adding the fish food. The betta I want is very expensive and I really want this to work out for the lil guy.

You can’t fold the sheet and place it in the filter for the new tank?
I too do fish in tank cycles. Never did one any other way. I never lose fish right away or anything. I go slow. I’m doing a 75 now and I added 7-10 small fish once per week or so. I had the tank running for over a month now and added some nerite snails, plants, ecocomplete, and driftwood to get the BB going. All is well.

 

You can’t fold the sheet and place it in the filter for the new tank?
I too do fish in tank cycles. Never did one any other way. I never lose fish right away or anything. I go slow. I’m doing a 75 now and I added 7-10 small fish once per week or so. I had the tank running for over a month now and added some nerite snails, plants, ecocomplete, and driftwood to get the BB going. All is well.

Hmm I’m not sure if I will be able to fold the sponge sheet. It is in a plastic holder I would have to break it to get it out. Plus the filter for the new tank is a sponge filter so even if I did fold the sponge sheet up I’m not sure where it would go in the sponge filter, it’s not like it has a bunch of inside space like HOB filters. I like your idea of starting off slow, I think I will add a few nerite snails before the actual fish.

If your 30 gallon tank has a heavy bio-load meaning lots of fish, running the new sponge filter in there for at least a month should seed it well enough to pretty well instantly cycle the new tank as long as there are fewer fish in the new tank as there is in the tank you use to seed the filter. There should be enough bacteria on the sponge filter to handle the bio-load of the one fish.

I have done this numerous times over the years and have never had an instant cycle fail me. I never get an ammonia or nitrite spike and always start seeing nitrates within a few days.

If you would feel more comfortable testing it before getting your fish though. Run the sponge for a month in the cycled tank. Set up the new tank. If you are going to use fish food as your ammonia source put some in there before you move the seeded sponge over. Wait until you see an ammonia reading before you move the seeded sponge. The bacteria needs food. If the next day after moving the sponge the ammonia has gone back to zero you will know that the sponge will handle the bio-load of your Betta. Either put your betta in there at this point or continue feeding the bacteria with fish food.

The 30 gallon has a snail and a giant goldfish. I am guessing the bioload for that is pretty decent considering goldfish are filthy. I think I will just add the sponge filter after it sits in the established tank for a while and slowly add the new tank inhabitants. I guess precise cycling is not as important for Bettas so I won’t worry about it too much. Thanks

 

The 30 gallon has a snail and a giant goldfish. I am guessing the bioload for that is pretty decent considering goldfish are filthy. I think I will just add the sponge filter after it sits in the established tank for a while and slowly add the new tank inhabitants. I guess precise cycling is not as important for Bettas so I won’t worry about it too much. Thanks

Cycling a tank is actually more for us than it is for the fish. We can go a bit longer between water changes if a tank has bacteria in there to consume the fish waste. With just the one Betta in a 10 gallon tank water changes will do the same thing a cycle will do. It will remove the fish waste.