Another "Great Debate" for the ages...

Grundy

"A Buckeye Behind Enemy Lines"
Jul 9, 2006
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Michigan
Not sure if this has been covered before but here goes: Have there been any head to head studies of canister filters with biomaterial versus HOB's with wheels for bioiltration? Specifically, if they both have about the same GPH rate has one been proven better. Just seems like this would have been studied at some point. Thanks!
 
i think (not sure as i don't have a canister) canister use those ceramic rings/balls/media or w/e for bacteria to grow on. they should be more surface area than a bio-wheel for the bacteria to grow on. not entirely sure though, just a shot in the dark.
 
my guess would be canister, because of the sheer amount of surface area for various bacteria to grow on. i've had a bio-wheel for a couple of years and even though this is no where near scientific, they just annoyed the h*ll out of me with their stupid spinning.
 
remember that in a 'debate' over how much media a filter can hold, and how much surface area there is in that media, a filter can grow only as much bacteria as there is nutrient to feed it. in other words, if you've got three small fish in a 100 gallon tank, the filter cannot be colonized by 'more' bacteria than there is ammonia generated by the fish. it doesn't matter if you've got a cannister or an HOB, nor does it matter how much surface area there is in each filter.

if on the other hand, you've got 50 large fish in that same 100 gallon tank (you wouldn't do that though, right?) then you'll need all the bacterial growing surface you can possible muster and only then does a discussion of how much surface area/media does a filter hold, make sense.

ok, now the drum roll and here comes the skimpy clad girl walking around the ring holding up that card telling us which round this is, ... and here come the filters with fire in their eyes. in the blue corner it's the cannister, with three media baskets full of porous substrate ready to do battle with the HOB-biowheel filter in the red corner. clang! and here they come, into the center of the ring .. the cannister throws a jab, the HOB ducks under it and throws a left which doesn't make contact. then, the cannister throws a right and .. and .. the HOB goes down. he's groggy, he's ... he's not getting up. it's all over folks. it's the cannister by a knockout! the crowd cheers ... well the crowd with the money. the cheap seats are aghast. they can't afford those cannister prices.
 
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Ah, the canister has the surface area...but it lacks the consistent oxygen source that is provided by the HOB. Let's say you had very little surface agitation, and no plants in the tank, and the top was well covered...you would have a lot less oxygen available to the bacteria in a canister filter if that were the case.

Not to mention the fact that this is all a pretty pointless argument owing to the fact that even with no filter at all, the bacteria have a whole tank area upon which to colonize. In other words, mechanical filtration is not necessary to biological filtration. So as long as your tank isn't overstocked and you're running adequate mechanical filtration, there really is no way any additional surface area would make squat of a difference.

But to address the original inquiry - I would say it's nearly impossible to do this scientifically. There are too many variables, plus I doubt there is a way to measure how much bacteria is in one filter vs. the other.

In my opinion, as far as bio goes, I hardly worry about it much. As long as there is something like biowheels or lava rocks or ceramic rings or what not - some place for the stuff to colonize which never gets replaced or rinsed in chlorinated water - then all is well. I choose canisters or HOBs based more upon purpose such as water flow, media options, etc than for biological filtration.
 
A lot of the reason for was question was just my own curiousty. I would think that a standardized solution of ammonia and water could be run through these filters or used in a tank and then the result looked at quantitatively. I realize that it is probably a moot point in real life scenarios. However, the numbers "5x" or "10x" the tank size have been thrown around for filtration rates. I also realize that biological filtration is probably the most important of the types of filtration for overall health of a tank. It just seemed to me that generic numbers like this would be dependent on the biological filtration capacity of the filter and not just flow rates. Just thinkin' ...
 
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