# Filter wool and filter flow



## LeeAberdeen (Sep 4, 2014)

Cleaned the secondary filter on my main tank yesterday, a Fluval 406, and couldn't believe the difference in flow after the filter wool had been changed. It had only been in there two weeks, but when I changed it the flow went from a trickle to like having the tap full-on, probably about 5-6 times as much.

I'm now wondering if it's better to dispense with filter wool altogether, and just have a top basket of a normal biological media, probably Matrix or Eheim Substrat Pro instead? That's what's in two of the trays, with biofoam in the bottom one, with the filter wool at the top. The filter wool's just there as a final polisher, but after only two weeks it was filthy and if it's going to block the flow so much, maybe it's counter-productive? I'd already dispensed with the polishing mat for the FX6 which is the main filter, and the flow on that is so much better too.

What does everyone else do? Do you 'polish' or see it as unnecessary?


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## Fishnut71 (Dec 7, 2014)

It simply comes down to how much water clarity you want. You've essentially set up your canister to be a polisher, and polishers are not meant to run long term. Filter floss in high density will capture more free floating particles, and ultimately will trap so much that nearly all access are clogged and the result is a decrease in flow....just basic physics. That's why most manufactured HOB filter pads are designed to only trap larger debris, so they don't clog up in a day.


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## DJRansome (Oct 29, 2005)

I use a fine filter pad, but not floss.


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## fmueller (Jan 11, 2004)

I love filter floss. In fact, it is the only medium I use in all my canister filters. How much flow vs filtration you get depends very much on how densely you pack it. It's a bit of an art, but you'll get the hang of it after some trial and error.


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## Fishnut71 (Dec 7, 2014)

fmueller said:


> I love filter floss. In fact, it is the only medium I use in all my canister filters. How much flow vs filtration you get depends very much on how densely you pack it. It's a bit of an art, but you'll get the hang of it after some trial and error.


Me too :thumb: I use poly-fill(pillow stuffing) from the craft stores


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## LeeAberdeen (Sep 4, 2014)

fmueller said:


> I love filter floss. In fact, it is the only medium I use in all my canister filters. How much flow vs filtration you get depends very much on how densely you pack it. It's a bit of an art, but you'll get the hang of it after some trial and error.


So how would you advise me to pack it? I buy a job lot of filter foam dirt cheap online and have been cutting it to size and laying it three or four-deep, but maybe that's too much? Does it need a gap for some flow to get through or do you cover the filter tray entirely with it? In my other tank I only lay it one deep, and it still blocks the flow.

Not sure about using it as "the only medium"? How does a polisher provide more than mechanical filtration, especially as you're presumably changing it regularly and disposing of BB as you do so? You'd have to change the pads alternately to avoid losing too much BB in one go which, if you had lots of them, would mean opening the filter every week or so? Just sounds like an eggs-in-one-basket scenario to me?


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## Fishnut71 (Dec 7, 2014)

LeeAberdeen said:


> fmueller said:
> 
> 
> > I love filter floss. In fact, it is the only medium I use in all my canister filters. How much flow vs filtration you get depends very much on how densely you pack it. It's a bit of an art, but you'll get the hang of it after some trial and error.
> ...


So, are you referring to filter floss or foam matting?

I believe when fmueller stated "it is the only medium I use in my canister", I'm sure he meant that its the only medium he uses for mechanical purpose, and not the only media in the canister


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## LeeAberdeen (Sep 4, 2014)

I guess you'd call it matting, really, or foam. It comes in big old sheets, anyway.

I'm sure you're right about meaning to say the only sort of mechanical filtration - it doesn't make much sense otherwise.


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## Fishnut71 (Dec 7, 2014)

Matting and floss are two different things. Floss is the stuff you find as pillow filler.

I'm guessing the foam you purchased has very small pores designed more for polishing or to be placed after foam that has larger pores.


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## LeeAberdeen (Sep 4, 2014)

I never mentioned floss, only "wool", because that's what it was sold to me as.

Yeah, it's more of a polisher, and has small pores.


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## Fishnut71 (Dec 7, 2014)

If you want to keep using this "wool" matting, then you will want to have a few larger pore foam/matting ahead of it. The larger pore matting will catch the larger debris and will only allow the fine debris to move to the wool matting. This will allow more time between filter cleaning.


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## fmueller (Jan 11, 2004)

Poly fill comes in matted form and loose - sort of like candy floss 

It is sometimes hard to tell what you will get, because for its intended purpose of filling a pillow, it really doesn't matter if it's matted or not.

I don't like the matted variety, because it is impossible to pack without leaving gaps. The loose stuff is much better, and when I say I use it as the only filter material, I mean the *only* filter material, period. Not just mechanical. Bacteria will settle on any surface, and this stuff has a lot of surface area. There is no reason it would provide only mechanical filtration. I've written up my thoughts on this issue in more detail on this page under "Filter media and filter maintenance".


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## LeeAberdeen (Sep 4, 2014)

fmueller said:


> Poly fill comes in matted form and loose - sort of like candy floss
> 
> It is sometimes hard to tell what you will get, because for its intended purpose of filling a pillow, it really doesn't matter if it's matted or not.
> 
> I don't like the matted variety, because it is impossible to pack without leaving gaps. The loose stuff is much better, and when I say I use it as the only filter material, I mean the *only* filter material, period. Not just mechanical. Bacteria will settle on any surface, and this stuff has a lot of surface area. There is no reason it would provide only mechanical filtration. I've written up my thoughts on this issue in more detail on this page under "Filter media and filter maintenance".


Interesting article. I think in this hobby, we all tend to think what works for us is the ONLY way to do it, which is clearly nonsense or there wouldn't be more than one way of doing it. Your system works for you, great, but I definitely won't be following suit, especially as one of the main reasons for doing it seems to be cost, and within reason I couldn't care less about that. I think if it was widely considered to be a good method of filtration, I'd have heard of others doing it before.

The idea of only opening a filter every three to four months, to me, doesn't work, especially when it's qualified with "because I am lazy". Are you doing it because it's the best way, which I've never heard anyone else suggest, or because you can't be bothered? The notion that you do it "so as not to disturb the bacteria doing their job" I can categorically state as nonsense, because cleaning a filter doesn't affect them if it's done properly, otherwise we'd all be having mini-cycles constantly. I clean all of mine once a month, and the water's well murky at the bottom, even without overfeeding. The idea of doing that with only filter floss in there, with its ability to become quickly clogged, seems even worse. You can stack it how you like, but there's still going to be an element of clog to it which is going to affect your filter flow. If cleaning filters messed with the bacteria as you suggest, that would be reflected in ammonia readings which remain unchanged.

I've decided I'm going to take the foam/matting out altogether and replace the top tray with afagrog. That works for me. Hope your system continues working for you.


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## LeeAberdeen (Sep 4, 2014)

I forgot to say, but it also defies logic to claim beneficial bacteria in the filter is so fragile as to be killed by a mere filter clean, then to be throwing out at least two-thirds, maybe all, of your filter bacteria when changing your floss. If your 'logic' about BB being badly affected by filter cleans was correct, it would also apply to you when you throw out potentially all of your media? If, on the other hand, you're right about tank fixtures and fittings containing a compensating amount of BB, so that losing filter BB doesn't matter (which I've never read anywhere else), then why bother mentioning it?


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## DJRansome (Oct 29, 2005)

I only clean canisters every 3 months or so...sometimes I start to clean one because the flow has decreased only to find a hose is clogged with MTS and the filter really is empty and not much to clean.

Polyfill sounds perfect to me except for throwing all of it away on occasion. Not much different that pot scrubbers which a lot of people use. Definitely covers mechanical and biological. I don't use chemical anyway.

So Frank do you think some anaerobic action get's going in the canisters after a time? I always do wonder why I don't have a lot more sludge.


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## fmueller (Jan 11, 2004)

@ LeeAberdeen

Your liberal usage of terms like 'nonsense', 'lazy' and 'couldn't care less' to me indicates a bit of a defensive attitude on your part. Of course I might be totally I misinterpreting that. There is so much that get's lost when we just read a forum posting rather than have a face to face conversation. At any rate, I am very sorry if I somehow managed to step on your toes. I had no intention of offending you.

I could not agree more with you than when you say there are a gazillion ways of successfully running a tank. Heck, there are even countless people out there who keep and breed fish successfully with old fashioned under gravel filters, even though the overwhelming majority of people on this forum (myself included), would say that this is an outdated and clearly substandard technology. Using filter floss and having long maintenance intervals in canister filters is also very old school, and in my humble opinion it's a technique that is well worth having another look at - especially if you are after efficiency both in running costs and in time required to maintain a tank. Good for you if you are in a situation where money is no issue and you are not interested in reducing the time necessary to maintain filters. I am not in that boat, and from moderating this forum for quite a number of years, I can assure you few CF members are.

Many thanks for pointing out the contradiction in my argument when I claim to be worried about disturbing the bacteria in a well established tank by too frequent filter maintenance, and then ditch the entire load of filter bacteria in one go. That doesn't make sense indeed, and I should rewrite the article in due course. The truth of the matter is that the concern for disturbing bacteria should be reserved for newly set up tanks. With a large filter full of loosely packed filter floss, opening the filter is just not necessary more often than I do. It takes a long time for clogging to become an issue, because the water continues to find new ways through the floss and loads it up with debris fairly evenly over time. When the time for maintenance comes, there are enough bacteria elsewhere in the tank, and I can afford to throw out all the old floss without any ill effect on the fish.

Apart from the throwing out of the media part, the process is quite similar to what happens with Hamburg Matten Filters, which also lean themselves to very long maintenance intervals: http://www.swisstropicals.com/library/mattenfilter/

@ DJRansome

Donna, for anaerobic decomposition to take place in the filter, obviously there would have to be zones in the filter where there is no dissolved oxygen in the water. Since the water I circulate through the system is at or near saturation levels regarding oxygen, I consider that to be extremely unlikely.

If there is anaerobic decomposition, it usually leads to a strong and very characteristic sulphide smell. I have smelled that when opening my filters, which is a blessing because my wife would ban me and the tanks from the house if she ever had endure that stink


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## Als49 (Jul 11, 2014)

DJRansome said:


> I only clean canisters every 3 months or so...


Me too. Sometimes sooner if the flow becomes slower.

I use Eheim Classic, and I believe I read somewhere in Eheim website that mentions about cleaning the filter periodically every few months. For more often maintenance, they recommend to simply back wash the filter, which is very easy and simple to do in a few minutes.


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## LeeAberdeen (Sep 4, 2014)

fmueller said:


> @ LeeAberdeen
> 
> Your liberal usage of terms like 'nonsense', 'lazy' and 'couldn't care less' to me indicates a bit of a defensive attitude on your part. Of course I might be totally I misinterpreting that. There is so much that get's lost when we just read a forum posting rather than have a face to face conversation. At any rate, I am very sorry if I somehow managed to step on your toes. I had no intention of offending you.
> 
> ...


You're definitely reading too much into that. I was just questioning, not having a go. Without reading the article again, I think "lazy" (or a synonym) was your usage, and the "couldn't care less" was a reference to myself and, within reason, my attitude to spending on my fish. I do believe, though, that the notion of cleaning a filter damages the bacteria is nonsense. As I said, if that was the case, we'd all be regularly undergoing mini-cycles.

Your comments did make me think about the reactions in the filter though, and I've now realised that my previous objections to any sort of dirt in the bottom of the canister is questionable. As you said, it's possible that there's some sort of beneficial process taking place with the bacteria actually multiplying in that soup-like stuff. Maybe cleaning a filter once a month is too much but, as I've had no problems doing it that way, I'll probably stick to that maintenance schedule.


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## fmueller (Jan 11, 2004)

LeeAberdeen said:


> as I've had no problems doing it that way, I'll probably stick to that maintenance schedule.


If it ain't broken, don't fix it 

Some time ago I had the good fortune of meeting Heinz Buescher. The name might ring a bell because N. buescheri is named after him. He has been on diving tours to Lake Tanganyika more times than most folks, has received an honorary doctorate for his ichthyological work, which he does as a hobby, and is all around a very humble and personable guy. One thing he said about the hobby really stuck with me, and that's that most of what he has learned over all the years is about stuff that's not required :thumb:


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