# Cleaning Filter Intervals



## nigel bentley (17 Apr 2020)

Good afternoon everyone, I was wondering if I could ask for some views on cleaning Eheim 2217 filters.

I have two Eheim 2217 filters for a 455 litre tank, running for 3 1/2 months. I change 30%water once a week but have yet to touch the filters. 
Water parameters are good and water flow is good, so a little unsure if I need to rinse filter or not.
I was thinking of cleaning one filter and then the other at one monthly intervals from now, obviously in fish tank water.

My main question is: As water parameters and flow from spray bars are both good, am I creating unnecessary work for myself?

 Any comments would be appreciated
Regards Nigel


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## Zeus. (17 Apr 2020)

I clean my FX6 out weekly on my 500l high tech tank, however I do tureky blast the carpet every week which gets lots of detritus being kicked up and I use the filter to 'catch it' then do the WC and then clean the filter media out and theirs plenty of detritus in the sponges. However your maintenance Technic may not generate is much detritus build up in your filter sponges, plus your tank is only 3 months old mine is over three years old. 

I would suggest to clean one out and see how bad/good it is and gauge it from there 

Cleaner is better IMO


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## dw1305 (17 Apr 2020)

Hi all,





Zeus. said:


> I would suggest to clean one out and see how bad/good it is and gauge it from there


Sounds a good idea. 





nigel bentley said:


> I change 30%water once a week but have yet to touch the filters. Water parameters are good and water flow is good, so a little unsure if I need to rinse filter or not.


It is going to depend on what media you have in them, if they just have biological media they are probably fine, if they have floss or fine sponge the water may be bypassing these. Because of the design of the Eheim Classics (water in at the bottom and out at the top) bypass tends to be less of an issue.

I just have coarse sponge and "Substrat Pro" etc in mine with a big sponge prefilter on the intake and they could go at least six months without any form of media cleaning. I usually only do mine when the hoses have got fairly gunky. 

cheers Darrel


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## nigel bentley (17 Apr 2020)

Hi Darrell,
One of the filters has a mixture of Eheim Mech, course filters, Eheim Substrate Pro and filter wool.

The second filter uses a small amount of Eheim mech, then approx 5 course filter pads  plus wool.

I'm thinking, rather than have a strict regime of cleaning filters, I will stick with just regular water changes and observe. Good point, looking out for mucky pipes as well as water parameters. Thanks Darrel


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## Andy Thurston (22 Apr 2020)

I clean my filters as little as possible. Moniter flow from your outflow pipes and when it is reduced clean the filter. When you have more than one filter it makes your life easier because you can stagger cleaning  and reduce the risk caused by overcleaning all your filters all at once


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## Aqua sobriquet (22 Apr 2020)

Unless I’m bored I’ve generally only ever cleaned filters if/when I notice a drop in flow. I also only rinse stuff that’s going back in tank water just to be on the safe side.


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## Nick72 (22 Apr 2020)

Interesting to see the comments above.

I breakdown and clean my canister filter on the first Saturday of every month.

The course sponges are normally pretty filthy by then. 

I suspect the filter would run without impeding flow for a great deal longer, but I don't want the canister to turn into a nitrate factory.


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## dw1305 (22 Apr 2020)

Hi all,





Nick72 said:


> I breakdown and clean my canister filter on the first Saturday of every month.


I'd clean the filter body more often if I didn't have a really large pre-filter foam on the intake. I give these a rinse every couple of weeks.

<"These are the ones"> I use on filter intakes, as well as powerheads etc.







Nick72 said:


> The coarse sponges are normally pretty filthy by then. I suspect the filter would run without impeding flow for a great deal longer but I don't want the canister to turn into a nitrate factory.


That is sort of the wrong way around for us.

You want the filter to be a nitrate factory, because you want all of the toxc ammonia (NH3) and nitrite (NO2-) to be converted to the benign nitrate (NO3). Because you've gone from NH3 to NO3, you've used a lot of oxygen, so I don't like anything in the filter that impedes water flow or uses "extra" oxygen. I just want oxygenated <"water (and the ammonia it contains) to enter the filter">.

Plants are very effective at mopping up all forms of fixed nitrogen, so NO3 levels are likely to fall in out tanks, rather than rising.

Some of the sellers of Matrix, Biohome etc. will try and persuade you that having <"simultaneous aerobic  nitrification and denitrification"> in a canister filter is a good idea, but they are, most definitely, wrong.

cheers Darrel


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## Sammy Islam (22 Apr 2020)

Generally i clean my prefilter weekly which catches most of the dirt. It also allows me to put back any shrimp that have made their way down there. I clean the filter body, tubing and glassware every 3 weeks. Cleaning tubes and glassware definitely helps improve flow, i didn't think it would help much to begin with.


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## Nick72 (22 Apr 2020)

dw1305 said:


> Hi all,I'd clean the filter body more often if I didn't have a really large pre-filter foam on the intake. I give these a rinse every couple of weeks.
> 
> <"These are the ones"> I use on filter intakes, as well as powerheads etc.
> 
> ...



Agreed a pre-filter will extend the cleaning duration.

I prefer not to have one in my tank and I'm happy to do more regular canister maintenance.

IMHO, and accepting that the main feature of a filter is to house beneficial bacteria for the nitrogen cycle, you still want to limit the amount of NO3 and certainly the variability of the NO3 being produced in the filter.

I'd rather control the amount of NO3 in the water column through dosing, than have the filter gathering ever greater organics and producing larger volumes of NO3 every week until it's serviced.

That's why I do a 70% water change and three daily doses of KNO3 every week.

I don't see any really advantage for the canister to produce ever more NO3 on a linear track every day between extended services.

That said I'm fairly new to the hobby and hear to learn - so I might be missing something.


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## dw1305 (22 Apr 2020)

Hi all,





Nick72 said:


> I'd rather control the amount of NO3 in the water column through dosing, than have the filter gathering ever greater organics and producing larger volumes of NO3 every week until it's serviced.





Nick72 said:


> IMHO, and accepting that the main feature of a filter is to house beneficial bacteria for the nitrogen cycle, you still want to limit the amount of NO3 and certainly the variability of the NO3 being produced in the filter.





Nick72 said:


> I don't see any really advantage for the canister to produce ever more NO3 on a linear track every day between extended services.


You are good, basically you don't need to worry about the filter producing ever larger amounts of nitrate. The amount of nitrate produced is entirely dependent upon the amount of ammonia present.

What happens is that each molecule of NH3 is converted to a molecule of NO3, assuming that you have sufficient oxygen. Once that NO3- ion is dissolved in the water, it just sits there until it is:

taken up by a plant,
removed by water changes or
anaerobic denitrified.
The issue with a clogged filter is an oxygen one, if you don't have enough dissolved oxygen you can get incomplete oxidation and levels of ammonia and nitrite can rise. If you don't have plants this is likely to prove fatal to your fish, in planted tanks the plants will usually take up the extra ammonia and nitrite.


Nick72 said:


> That's why I do a 70% water change and three daily doses of KNO3 every week.


We like water changes.

Have a look at the <"Duckweed Index"> it is a technique where you use the growth <"and leaf colour of a floating plant"> to assess the nutrient level in your tank. 

cheers Darrel


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## Aqua sobriquet (22 Apr 2020)

My shrimps and plants are going mad in my 37L Nano. The filter gets cleaned once every few months and I do a 10-15% water change once a week if I remember, which sometimes I don’t. It looks like the inlet and outlet pipes may need a clean once a year and the hoses every 4 or five months by the look of it.


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## jameson_uk (23 Apr 2020)

I have the Eheim pre-filter on my 2217 where the sponges get a weekly rinse.
The filter itself gets cleaned about once every 12 weeks (the pipework also gets a clean in the few weeks following cleaning the media).
I have the EfiMech, 2 coarse sponges and some Substrat Pro (No filter floss).  

This seems to be a good schedule and the filter is now a bit manky when I clean it.   Previously (before I sorted out flow, the pre-filter proper maintenance...) when I opened the filter the top was floating with lots of debris and was generally manky.   Now it seems that the gunk has generally made it to a few cm below the top of the media so I could probably go a bit longer but this schedule seems to keep things OK.

Is going to depend on stocking, cleaning schedule etc. but you should be able to gauge it by just how dirty it is when you open it.


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## jaypeecee (23 Apr 2020)

dw1305 said:


> You want the filter to be a nitrate factory, because you want all of the toxc ammonia (NH3) and nitrite (NO2-) to be converted to the benign nitrate (NO3).



Hi Darrel,

On the basis that plants preferentially uptake ammonia instead of nitrate, why would we want the filter to be a nitrate factory?

JPC


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## jaypeecee (23 Apr 2020)

jaypeecee said:


> On the basis that plants preferentially uptake ammonia instead of nitrate, why would we want the filter to be a nitrate factory?



Hi Folks,

Perhaps I didn't make myself clear with my question above. I thought the idea was to let plants take up all nitrogenous waste from the fish and other inhabitants. In other words, plants would mop up ammonia, nitrite and nitrate. Consequently, the amount of nitrate in the tank would always be controlled at a safe (!) level for the inhabitants. The filter would then not produce nitrate as it is not required to perform biological filtration. Furthermore, plants have the capacity to absorb heavy metals. Diana Walstad deals with this in some detail in Chapter 2 of her book _Ecology of the Planted Aquarium_. So, The main function of the filter would be to create flow, mechanical filtration (particles) and removal of organics using activated carbon, for example.

Since getting into the world of aquatic plants, I was under the impression that what I've outlined above was the preferred approach by planted tank enthusiasts. Looks like I may have got the wrong end of the stick!

JPC


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## jaypeecee (23 Apr 2020)

dw1305 said:


> The issue with a clogged filter is an oxygen one...



Plus the fact that a clogged filter will release phosphate and other compounds back into the water column. And it reduces flow rate.

JPC


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## dw1305 (24 Apr 2020)

Hi all, 





jaypeecee said:


> I thought the idea was to let plants take up all nitrogenous waste from the fish and other inhabitants. In other words, plants would mop up ammonia, nitrite and nitrate. Consequently, the amount of nitrate in the tank would always be controlled at a safe (!) level for the inhabitants. The filter would then not produce nitrate as it is not required to perform biological filtration.


It is always <"plant/microbe filtration">, even if you don't have a filter. 

I don't care where the nitrification occurs, I just want a situation where the dissolved oxygen level <"always comfortably exceeds the Biochemical Oxygen Demand (BOD)">, and I don't think it matters <"how you get there">.





jaypeecee said:


> preferentially uptake ammonia instead of nitrate, why would we want the filter to be a nitrate factory?


If it was a <"plants only" tank>" then urea or ammonia would be fine as a nitrogen source, it maybe a trigger a for <"algal spore growth">, but we don't really know. 

Plants take up all forms of <"fixed nitrogen"> I don't think it really matters that much what form it is in. Most fertilisers for terrestrial plants use either ammonium nitrate (NH4NO3), or urea (CH4N2O), because you get most <"bang for your buck"> and you haven't added another salt. 





jaypeecee said:


> Looks like I may have got the wrong end of the stick!


It isn't anything to do with the plants, but as soon as you have livestock you need to keep the ammonia (NH3) and nitrite (NO2-) levels as low as possible because they are sub-lethal at very low levels, and lethal at slightly higher ones. In the case of nitrate (NO3-) <"we really don't know at what level it becomes toxic">, but it looks like it is certainly in the hundreds of ppm and quite possibly another order of magnitude higher for many fish.

Horticulturalists would look on potassium nitrate (KNO3) primarily as a potassium source, but it is really useful to planted tank aquarists, because it contains two elements plants need and it doesn't contain any ammonia. 

cheers Darrel


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## jaypeecee (24 Apr 2020)

dw1305 said:


> It is always <"plant/microbe filtration">, even if you don't have a filter.



Hi Darrel,

That being the case, I can see nothing wrong with having a healthy biological culture in the filter. And I choose to use an ammonium compound to start the process. But that warrants its own thread - sometime.

JPC


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## jaypeecee (24 Apr 2020)

nigel bentley said:


> I'm thinking, rather than have a strict regime of cleaning filters...



Hi @nigel bentley

That's the approach I take. I think it was Fluval that incorporated a TDS sensor inside one of their filter ranges. The G something or other, maybe? It's not perfect by any means but monitoring TDS/conductivity over a period of a few months could potentially be helpful. Of course, this isn't just monitoring the filter but the tank water. Observing the tank inhabitants - animal and plant - is obviously very important.

JPC


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## dw1305 (24 Apr 2020)

Hi all, 





jaypeecee said:


> I choose to use an ammonium compound to start the process


It would be back to the nature of the microbial community.

It looks like the nature of the assemblage is <"dependent upon the level of ammonia">, and that <"initial high levels of ammonia"> will create an assemblage that is different from the <"stable long term assemblage that we need">.  There is further discussion of this in Koch _et al._ 2019 <"Complete nitrification: insights into the ecophysiology of _comammox_ _Nitrospira_">

What I don't know is how long it takes the microbial assemblage, that <"we want, to establish">. This is partially because it will develop step in step with plant growth in our aquariums and it would be very difficult to partition the effect into separate "plant", "microbe" and "interaction" pigeon-holes. As an example as the plant roots radiate through the substrate they will introduce oxygen (via <"Radial Oxygen Loss">) and they will produce exudates to which will alter the nature of the microbial community, it is a <"synergistic process">.

I haven't found anything specifically for aquarium filters, but there is quite a lot of research on <"Constructed Wetlands">. There is some data from <"waste management">, including <"_Myriophyllum aquaticum_ Constructed Wetland Effectively Removes Nitrogen in Swine Wastewater">

This is from <"Nitrification in multistage horizontal flow treatment wetlands for landfill leachate treatment">.





> The NH4+-N removal was correlated with inorganic carbon consumption followed by NO3− production, which suggests that nitrification was the major route of removal. For both systems, nitrification was significantly higher in one of the units, when biodegradable OM was already consumed and competition between heterotrophic and autotrophic bacteria for dissolved oxygen was likely minimized. By balancing the organic load and availability of dissolved oxygen within each unit in series, a reduced HRT necessary for NH4+-N oxidation was achieved, an essential aspect for the design of high performance constructed wetlands for full scale landfill leachate treatment.


cheers Darrel


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## jaypeecee (24 Apr 2020)

Hi Darrel,

Yes, I already have many of the papers that you listed - and a few extras. They are all very interesting indeed. I know of someone on A N Other Forum who devised an experiment to gauge how the processing of nitrogenous waste was 'split' between plants and microbes*. I seem to recall that it was about 50:50. But, this experiment would need to be re-run. I haven't been in touch with that person for at least a year.

* bacteria _and_ archaea

JPC


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