# Does changing the filter upset the nitrogen cycle?



## opus2000 (Jan 20, 2011)

I have been learning so much here about cycling my first tank. I have read several references to the beneficial bacteria growing in the filter. My tank's instructions say to change the filter every approximately every 6 weeks. Does changing the filter mean the cycling process starts all over again? Or is there enough good bacteria in the gravel, on the tank decorations, etc., to keep everything balanced?


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## LittleBettaFish (Oct 2, 2010)

Probably 99.9% of your beneficial bacteria is found in the filter simply because it's the environment best suited for it. The rest of the bacteria would be found in your gravel and water column, but in amounts so negligible that they have little impact on maintaining the cycle in your tank. 

That's why large water changes will not usually disturb your cycle, but changing out the filter pad will cause it to crash. 

The only reason companies tell you to change out your filter media every six months is because a) some of the media in your filter is carbon, and it becomes useless after a certain amount of time (but does provide another surface area for your beneficial bacteria to colonise) and b) they want to make more money off you. 

I have had a goldfish tank running with two filters for about two years now, and aside from a gentle swish every now and then in treated tank water, my sponges have never needed replacing


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## c4talys7 (Sep 7, 2010)

I was trying to find the answer to this too, I'm glad someone else had the question. Will rinsing the filter holder ruin the cycle? Or getting all the gunk off the sides of the tank ruin it as well? I noticed a lot of build up while cycling.


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## LittleBettaFish (Oct 2, 2010)

Scrubbing something like a clear film off your aquarium walls should have no effect on your cycle. You can also safely dunk your filter in a bucket of old tank water to dislodge any organic debris, and maximize water flow/filter performance, as well as wipe off any algae growing on the outside surface. 

However, I wouldnt' scrub the *inside* of the filter too vigorously. There will be enough beneficial bacteria colonising not only the filter media, but also the inside of the filter itself, that it could upset your cycle if you are continually cleaning. The only time I rinse my filter media is when the indicator on top shows that it's blocked.


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## opus2000 (Jan 20, 2011)

So, should I just rinse the filter sponge and change the carbon media inside, rather than replace the whole thing?


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## Canuck Fins (Oct 5, 2010)

You really don't need the carbon if you are cycling the tank.


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## c4talys7 (Sep 7, 2010)

Ok thank you! I just notice that there is some junk getting sucked into my filter and just wanted to get those out, so probably a quick dump in old tank water would do it?


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## demonr6 (Dec 27, 2010)

I have the filter sandwiched between two Fluval sponge filters. If I ever need to replace the filter I have the sponge filters that should be colonized with the same bacteria as the filter as well. That is my theory and I hope it is sound enough to work. Anyone care to comment or offer advice on that idea?


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## ChicagoPete (Dec 27, 2010)

Also take note to never use tap water on the filter to clean it. Only the used tank water or bye bye colony. Dip the filter media in the water and then lift it and let the water drain out of it. Gently rub and pluck the fiber clean from extra debree under the water and swish it around a bit in it, followed by a few more dunks and letting it drain.


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## c4talys7 (Sep 7, 2010)

Of course lol, I will keep that in mind as well seeing as I really don't want to deal with that smell again after cycling.


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## ChicagoPete (Dec 27, 2010)

hmm what smell are you refurrin to?


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## c4talys7 (Sep 7, 2010)

Well the decaying shrimp smells kinda unpleasant. It is in panty hose in the water but has started floating so the smell is more apparent now. I believe it is floating though because of the decay is has made a "bubble" around itself and filled with the decaying gases has caused it to float. I head from several people that the smell is normal.


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## ChicagoPete (Dec 27, 2010)

Eww ahaha.... But yah now I see what your sayin about it as a good thing.


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## c4talys7 (Sep 7, 2010)

Yeah, luckily for my roommate she can't smell it at all. Not to lucky for me lol


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## scootshoot (Oct 11, 2010)

Just rinse your filter medium in tank water. Only change it if the medium is falling apart.


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## Oldfishlady (Mar 1, 2010)

As posted by others-a lot of the beneficial bacteria colonize in the filter media and it is best to give it a good swish/rinse in old tank water with a water change a couple of times a month and when the water flow slows to maintain good water flow

If you ever need to change the filter media-in young setups it is best to cut a piece of the old sponge off and add to the new sponge for a week or so to seed the new sponge

With mature setup (6mo and older) with a mature stable nitrogen cycle that is not over stocked.....you can usually replace the sponge without any problems

If you want to use carbon and your filter media is the combo type that is the sponge and carbon in one....you can cut a slit in the filter media and dump the carbon out and just use the sponge part or even add fresh carbon to this if you cut the slit in the right place

Carbon is usually not active and/or used up in about 3-6 weeks and needs to be replaced....however...you really don't need carbon IMO...especially when a water change will do the same thing....remove-odors, tannins, any discoloration in the water, medication....with that said...it is still a good idea to have fresh carbon on hand......just in case...example...some type of toxin got in the tank or you just want to clean the water a bit more to make it clearer, heavy metals or overdose of medications and you want to make sure it is all out......IMO-you don't need carbon on a regular basis....

Filter media-you shouldn't have to change this out unless it is falling apart.....it still needs a swish/rinse on occasion to maintain that water flow or otherwise the good bacteria will not get enough oxygenated water and start to die and their byproduct is ammonia.....

Same with the ceramic beads that never need replaced-sometimes they will need a rinse-if they become clogged with lots of organic matter it can hinder oxygenated water flow and your colony of beneficial bacteria can die or not thrive as well

I look at cost because I have lots of aquariums...I have filters on some of them but it is more for water circulation..... the live plants are the true filters in my tanks...so I make my own filter media with poly-fill to trap the large debris and the HOB boxes sometimes end up being a shrimp nursery...lol.....

But if you only have one or a few tanks and/or you have the funds to buy and replace filter media and/or carbon....nothing wrong with that either.....new filter media and carbon use is a personal choice as much as anything else....IMO....


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