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Just got a new external filter......is this the correct way to cycle it ?

Goose3080

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At the moment I have an All Pond Solutions external canister filter, its fully cycled, its a bit wimpy so my wife brought me a Fluval 307 filter, obviously this filter wont be cycled, so what im thinking of doing is leaving my current one in place, however, connect the out from the old filter to the in of the new filter, then the out of the new filter back to the tank, and leave it to run like this for about 8 weeks, would this be an OK way to cycle it, this is hoping the good bacteria from filter 1 passes over into filter 2, (crude picture below), the wave maker at the other end of the tank is to stop any stagnant area's
 

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You won't really have any problems with cycling if you just put your old filter media from your old filter into the new canister filter. Or you could run as shown in the diagram with 2 canisters running parallel.
 
You won't really have any problems with cycling if you just put your old filter media from your old filter into the new canister filter. Or you could run as shown in the diagram with 2 canisters running parallel.

Thanks, theres not really any room in the new filter for the old media, unless I cut it up into small pieces and pop it into any available gaps, the sponges in the old filter are quite big.
 
What you have in the picture would work. And you could just use mechanical filtration for your first filter, then you can put all sorts of biological media into the second filter.
 
What you have in the picture would work. And you could just use mechanical filtration for your first filter, then you can put all sorts of biological media into the second filter.
Thank you, but my intentions are to get rid of the first filter in a few weeks once the 2nd is cycled.
 
I would be worried about the outlet of the old filter vs the inlet in the new one.

If you use one filter what goes out comes in again by vacuum / syphoning. If one uses two different filters it could be causing issues cause one might have to much power fot the other. I wouldn't put them in line cause of that but use them seperate or only use one (the old media swapped).

I have seen the lineversion working with exact the same filters btw
 
Adding filters does not create more bacteria, only more ammonia will do that.

The bacteria live in the greatest concentration where they can get the things they need delivered to them. A few bacteria are always motile, but for the most part they are attached to hard surfaces via a bio-film.

So, forget the idea of hooking the two filters together. This will do nothing to help with bacterial relocation and may cause issues. So what will work? Step one is to understand how to get bacteria out of the old filter and into the new one in light of the info above.

What you need to do is to make the old filter less hospitable to bacteria and the new one moreso. This can be done as follows.

1. Set-up the new filter one the tank with no connection to the old filter. Moving over old media with bacteria from the old to the new filter would be the most helpful. This is true even it it is only a bit of the media. If you cannot do this there is another way. Turn of the old filter and leave the new one running. Then rinse out the media from the old filter in the tank. The goal is for it to end up in the new filter. You can leave the old filter off for an hour to facilitate this process.

2. Make sure the new filter is running at its full flow rate. Slow the flow rate in the old filter without stopping it entirely. What you are trying to do is make the old filter less effective which will make the bacteria now inside the new filter re[produce faster. Over the next two weeks or so begin to remove some of the bio-media from the old filter which will result in the bacteria reproduce more in the new one.

3. A lot of the good bacteria in tanks is actually not in the filter. It is in the substrate, on plants, rocks and other decorations. Bear in mind that the bacteria is somewhat photophobic (it doesnt like light, especially bright light). So it will be in shaded or dark places in one's tank and filter. This is why filters are not made of clear materials. ;) Your filter is a good home for bacteria but is far from the only place iin a tank the bacteria are living.

4. The bacteria multiply faster when there is more ammonia/nitrite than they need. Conversely if these things are reduced, the bacteria will slow their reproduction. If the supply drops below what the colony needs to thrive, they will die faster than they reproduce and the colony size will shrink to be in balance with the lowered supply of ammonia/nitrite.

5. The bacteria in your old filter is not going to pack up and move to the new one. What will happen is a bit of the bacteria will get into the new filter and colonize. But it cannot go crazy because most of the ammonia is being used by the bacteria in the old filter. So what you are doing following the above plan is making the old filter increasingly less able to support the needed amount of bacteria while the new filter becomes a much better home for the bacteria.

6. Monitor ammonia levels during the changeover. Hopefully you will never see an ammonia reading during the changeover. But if you do, a water change will fix that.

7. Finally, bear in mind that, under optimal conditions that the ammonia bacteria can double in numbers in about 8 hours while the nitrite ones in a few hours more. The odds are very good that you can make the changeover and have no issues doing it.
 
Too late, but what I did before hand was take some of the tank water out into a bucket, dismantle my old filter and rinse the sponges out in the water in the bucket, this went a mirky brown, i then rinsed my new filters in the mirky water, fitted everything together and set to run, the old filter isnt even switched on, the new filter and pump is doing all the work at full power

 
The best way to start a new filter when you have an existing filter on your tank, is simply to move the media from your old filter onto your new filter. This may mean taking out some of the new filter media which is not seeded in order to place the old filter media in there. Will the filter work differently with the old media versus keeping all the original media? No not at all.

I tend to disagree with those who say that there's more beneficial (or an amount with the ability to keep the cycle) bacteria in the substrate and in the tank versus in the filter for two reasons. Filter media is constructed or sought out because it has the ability to house the most beneficial bacteria in the smallest space. If you have your filter setup correctly (where the beneficial bacteria media is one of the last to receive the water) then you should have the best numbers of beneficial bacteria in your filter media. Is that not saying that there's other beneficial bacteria in your tank, no I'm not saying that. However I have transferred many tanks and restarted them from scratch and the only thing that had bacteria in them is the filter and it had completely cycled my tank from day one without having to cycle all over again because all of my beneficial bacteria was alive in my filter even though my tank was 100% new and clean including the substrate. So what I am trying to say, probably not too well, is that if you have a 100% cycled filter with filter media in it with a good colony of beneficial bacteria, you can set up a brand new tank without a cycle. I have done many times. And I have restocked my tank with the original fish that we're supposed to be in the tank without any harm to the fish. How do I know this? I have moved multiple times and in the moving I've had to break down tanks entirely. Not having containers to hold substrate or wanting to haul substrate from one house to the other, it was cheaper for me to buy new substrate and start from scratch. When I reset the tank I may have used some of the old driftwood but I added new driftwood and decor, the only thing that was essentially used / reused was my filter. Did I believe that I was not going to have a cycle crash or have to restart a cycle, no. I did carefully watch my tank but the established filter avoided any cycle crashes and I did not have to recycle my tanks.

So the moral of my long rant is that you do not need to count on the bacteria that is in the tank in a substrate and the driftwood or the decor, on the walls wherever else BB may occur, because it is the filter's bacteria that is keeping the cycle in your tank. Be it sponge, fancy plastic balls, glass rings, ceramic, this media has been formulated to house beneficial bacteria in larger quantities and in a smaller amount of space and in better conditions for bacterial growth than in other areas of your tank. If it wasn't efficient at growing beneficial bacteria, there would be no market for it.

Additionally the amount of BB needed for your tank is a set amount. Your fish waste is a constant providing only a set amount of food for the bacteria. No matter how many filters you have if the bacteria is already established in the one, very little to no bacteria will grow in the new one unless needed (i.e. extra fish, excess food, removal of established filter/media).

Sorry if somethings are not 100%. Microphone tends to interpret things and it's surprising how Covid tends to make you less concise with wording and concepts.
 
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