Let's talk mechanical vs bio filtration...

W

wiEngineer

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Aug 25, 2002
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Madison, WI
I originally purchased my 55g tank in a package witha Millennium 3000 HOB filter. I hate this filter due to problems with water bypass.

I purchased a Filstar XP3 canister filter to replace the M3k and have been very happy with it (there's an issue with air getting into the canister, but its not relevant to this thread).

About 2 weeks ago, I removed the M3K filter after having the XP3 cycle for about two months. It is filled with ceramic tubes, crushed lava rock, and some nylon sponges for media with a nylon pre-filter sponge over the intake (my thinking was that the XP3 would become a good biological filter).

Within about a week of removing the M3K, I started to notice how "cruddy" my water was getting. Too much fish poo floating around for example. A water test showed Ammonia and Nitrites at 0 zero, so the XP3 was working well, just not sucking up the gunk.

My thinking at that point was that the XP3 wasn't providing enough mechanical filtration so I reattached the M3K filter and within about 12 hours things had greatly cleared up. Unfortunately, I'm still using that craptacular HOB filter I hate.

So, I'm looking for some thoughts here. I've read that my idea of using the canister as a biological filter may not be sound (no air, no light) and instead I could outfit it as the mechanical filter (remove the pre-filter, maybe re-arrange the media, etc), then mate it with something like an Aquaclear 300/500 HOB or some kind of a bio-wheel HOB and let that become the bio-filter.

One of my primary goals here, however, is QUIET. Even the gentle trickle of my M3K gets on my nerves after a while which was my primary reason for going to a canister (tank is in living room). However, I also don't want a tank that is unhealthy without a good HOB providing counterpoint to the canister.

Regrettably, building a wet/dry sump for this tank isn't an option.

Any thoughts here? I didn't post this in DiY/Product review because I'm trying not to focus on specific product, but more in approaches I could take.
 
IMHO, canisters work best as biological filters. None of my canisters match up to any of my Aquaclears in terms of mechanical filtration (comparing appropriate sizes of course). IME, its flow rate that determines how well a filter will do in terms of mechanical filtration.
For example, my Eheim 2026 canister will never compare to my aquaclear 500 in terms of mechanical filtration... just based on the fact that my aquaclear has a high flow rate than the canister. However, my aquaclear 500 will never compare to the canister in terms of biological filtration because quite frankly, that filter has several times more bio capacity than the HOB. IMHO, keep the pre-filter on your canister and leave it as a biological filter. If you don't like your current HOB, get another one. Aquaclears are good for mechanical filtration. Stick in one of those aquaclear sponges and some filterfloss and you got yourself a pretty effective mechanical filter.

HTH
-Richer
 
Using a canister as a mechanical filter is not a good idea. Mainly, because servicing canisters is not the easiest task. And you need to clean your mechanical filters often enough not to allow the particles to decompose.

Using them for biofiltration only is a very good and sound idea, IMO. That's how I use all my canisters. You can read a very good article on the subject here: http://www.tomgriffin.com/aquamag/cannister.html

As for the mechanical filtration, I'd, personally, go for a H.O.T. Magnum for your tank size. It's very effective, reliable and versatile.
Some people like internal filters for the job. I hate internals (too awkward to service, and they look ugly), but this is my personal opinion.
 
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i sort of think of my fluval as a biological filter but it does mechanical too. i had an abortive attempt at live plants and i have alot of things that eat them so i had alot of leaves that got stuck to the un-prefitered intake. some got sucked in too i'm sure. with the fluval i really don't think it's a big issue to split it open and clean the main sponges. i have no idea how filstar works with this....... i also tried to pre-filter my fluval with a nylon when i had fry nearby and noticed it restricted quite rapidly, even to the point it was literally crushing the screen with vacuum. you would think the nylons would just stretch somewhat as they restricted and allow the water to pass...... i also noticed at that time that i was picking up some air in the impeller because the pump was literally spinning too fast and churning the inadequate water supply so hard as to make bubbles..... i also noticed crud accumuating on that end of the tank.

my conclusion? skip the pre-filter if at all possible. what is happening to you is sounding alot like my experience.

i would also suggest you add more topwater filtration with another hob, but thats just me personally. i'm not sure how well aq's do for noise, but i would definately buy one. personally i use emperors tho and the noise usually isn't noticed........

top water filters would have to work better mechanically i would think because it is a much shorter run and alot less restricted for larger waste particles to get sucked in. by extension you would think they would have a much better turnover rate........

i think they both have their place in a well running tank and like to have one of each.

sorry if this is rambling...........
 
You can't have bio filtration without mechanical,they work hand in hand.The bacteria colonies need the stuff that got sucked up by mechanical means to convert ammonia and so on.
 
Serra, as they describe mechanical filtration, they're referring to seperation of particulate matter from the water. Yes you will have some bacteria colonize on the media, but it will not grow to a useable colony b/c of the accumulation of particulate matter (which will suffocate the bacteria).
When a seperate filter is set up for bio-filtration only, the pre-filter keeps particulate matter out of the media which prevents suffocation of the bacteria. Then, only water (along with nutrients like ammonia and nitrite which the bacteria need)is able to flow through the filter. This reduces maintenance on the bio-only filter, though the pre-filter must still be cleaned.
 
Originally posted by Serrateeth_2002
You can't have bio filtration without mechanical,they work hand in hand.The bacteria colonies need the stuff that got sucked up by mechanical means to convert ammonia and so on.
Click to expand...

??????????????

The best of use of mechanical filtration is to remove particulate matter BEFORE it breaks down and contributes to the load on the biofilter. The biofilter can survive quite nicely on just the ammonia produced by the fish, thank you very much. Just like when you fishlessly cycle.... nothing for the bacteria to eat but ammonia.

If you leave the crud in the tank, it's just going to be reduced to nitrates and other dissolved compounds (i.e., pollution) so why leave them in there? No good reason to...

Jim
 
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