# Advice/Info wanted regarding Over-Filteration



## niru (14 Sep 2011)

Hi

what are the effects of over filteration in planted tanks? Plainly I would think that if plants are doing well, they provide most of bio-filteration & also chemo- to a large extent. So most filters anyway act more as mechanical cleaners. 

Any inputs, links to where I can get more info on this are most welcome.

thanks
niru


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## Katch (14 Sep 2011)

Over-filteration is more a side effect of wanting good flow and turnover in planted tanks.

The actual over-filteration has very little impact on the tank eco-system.


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## niru (14 Sep 2011)

Thats what I also thought! Does this also mean that the time interval between individual cleaning sessions would increase as the same amount of dirt is captured at more places, or does the increased turnover lift more dirt thereby cleaning the tank more & not actually helping to reduce the filter cleaning frequencies..


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## Katch (14 Sep 2011)

In my experience it makes no difference. I think a lot of people clean out their filters a lot more often than they need to. The filter manufacturers have done a good job in spreading the myth that it needs to be done all the time and that we need to buy new media each time.

Mine go months without cleaning with no issues.


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## niru (14 Sep 2011)

I have observed that the mulm thats sitting inside the filter (when cleaning it, say) contains a lot of Iron (& related) precipitates (it has that typical metallic stink). If there are less filters, this means that theres more of these precipitates in the tank substrate, and not inside the filter. Plants can make good use of them. However with more filters & more flow etc associated with it, will this actually decrease the amount of detrius & micro-ferts that we add??

Effectively, would doing over-filteration clean our tanks more, but also demand higher levels of EI dosings, since more of these ferts will be sitting/precipitated inside the filters & not in the tank?


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## Katch (14 Sep 2011)

The whole point of EI is that you provide substantially more of everything than the plants could possibly need. I don't think over-filteration would impact on dosing at all.


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## niru (14 Sep 2011)

Katch said:
			
		

> The whole point of EI is that you provide substantially more of everything than the plants could possibly need.



Thats quite clear    

My question is how does over-filteration affect the tank in all its aspects: dosing, bacteria, dirt hoovering, maintainance frequency, plant response (flow-wise some come from gentle streams, some from rapids, some are river/lake/marsh inhabitants), etc...


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## ceg4048 (14 Sep 2011)

Hello,
        Hi filtration turnover rates has the positive effect making more oxygen available to the bacterial colonies within the filter media stack. This then enables a higher conversion rate of NH4 to NO3. This then enables the hobbyist to increase the fish loading.

The increased flow from the filter also increases the removal of waste in the tank thereby keeping the tank cleaner. If the distribution is good then the debris that tends to settle on the surface of the leaves has a higher probability of being removed from the bio-film. The debris includes detritus and carbohydrate products being produced by the plants themselves. The secondary effect of the debris removal is that there is less blockage of gas and nutrients across the leaf/water interface thereby improving nutrient/CO2 uptake, which generally improves plant health.

Greater carbohydrate, nutrient and Oxygen transport to the filter media stack from the tank area improves the health of the bacterial colonies within the stack because bacteria require CO2, O2 and nutrients as well as NH4.

This is why I prefer adding greater flow to a tank via more robust filtration in lieu of simple powerheads. Of course, higher flow through the filter which then deposits higher levels of debris should be addressed by more cleaning of the filter. If there is too much organic waste buildup in the filter beyond the capability of the bacteria in the media stack to consume NH4 then this tends to encourage the rise of BGA.

I think you will find that in CO2 enriched tanks, stronger filtration rates are highly correlated to healthier plants and reduced occurrences of algal blooms, especially as the plant bio-mass increases.

Cheers,


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## niru (15 Sep 2011)

Hi Clive,

thanks as always mate! What you mention is all in line with the expectations & your persistent advice on improving flow. My questions stem from the following: 

In my 180 l tank I have 1 internal filter (Juwel pump @ 1000 lph), and had 1 Eheim cannister @ 600 lph with CO2 reactor on the output side. Plus I had 1 Koralia nano for flow reasons. So this is in line with 10X flow rule. I understood that the rule-of-10 as such is for the stated filter ratings (without any load heads). 

Last weekend, my Eheim broke (the handle-shaft that seals & primes went kaput). Seeing this as a good opportunity to upgrade my filter, I got a Tetra EX with 1200 lph. But now this week, I managed to DIY the Eheim shaft & can hopefully start it running as well. Of course I have removed the Koralia, but still was wondering if I use all the 3 filters, I will get a total stated flow rate of 2800 lph. Even with a 50% reduction due to plant mass, fliter-media, etc I will still have a massive flow in the tank. Since it is spread via spray bars across the entire tank, plants & fish arent going to blow away, but it is surely more than a gentle breeze.

Would this be beneficial to the overall tank health, and what "issue" should I be aware of? Plus would this help in prolonging the filter cleaning intervals?

-niru


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## ceg4048 (15 Sep 2011)

Hi mate,
                The only thing you have to worry about is whether the velocity is too much for you fish. There are no negative ramifications. Your tank will be cleaner both from a clarity standpoint as well as biologically. Just carry on. To save trouble clean only one filter at a time at alternate intervals. Shrink the interval if the filters seem excessively dirty and expand the interval if the filters seem relatively clean.

Cheers


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## niru (15 Sep 2011)

Great!! Thanks Clive.


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## Garuf (15 Sep 2011)

So ceg, are you saying there's nothing in this EU concept of having tiny filters turning over around 2-5xtank volume per hour and then getting the flow up using pumps a-la reefers? They seem to get good results but I never figured out why, is it just a matter of there being a very low bioloading?


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## ceg4048 (16 Sep 2011)

Hi Gareth,
                 Well there are different ways to skin a cat right? As well, there are different issues and nuances. Flow/distribution and filtration are completely separate issues. So for example if I intend to have a high fish stocking then I neef to think about high turnover and high capacity filtration. Just having high flow rate from a powerhead won't help. This is obvious to most people when we talk about fish because everyone knows that having lots of fish generates lots of waste. Somehow, people seem unable to make the logical leap when it comes to waste generated by high biomass of plants. In a tank chock full of plants (in a CO2enriched tank anyway) a fairly high percentage of the dirt being generated is actually being generated by the plants, not the fish.
So really, the same rule applies as regards overstocking and filtration requirements as it would if there were lots of fish in the tank. The fact that higher capacity filters also have high capacity pumps automatcally means that you get benefits of both high flow to solve the nutrient/CO2 uptake issue, and high filtration to solve high biomass/waste generation issue in one package.

If there weren't lots of plants or fish in the tank then the powerhead solution would be just as effective because the tank would not be burdened with do much generated waste. Non-CO2 tanks, having much slower metabolism and much lower waste generation also are less critical of low capacity filtration.

Cheers,


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