Is more really better? Filter turnover.

[Bderick67]

After reading Johnptc's poll on filter turnover;
http://www.monsterfishkeepers.com/forums/showthread.php?t=56742
I was amazed how many people base their filtration on number on turn over.

To me this is only a part of the equation. You have to consider type of filter, type of media and amount of media, and of course bioload.

price range not a factor.

So heres a hypethetical tank set up tell me what is better.

100 gallon tank, fully stocked we are gonna go for 5x turn over rate. so 500 gallons per hour.

1 AC110 at 500gph or 2 eheim 2026 canister filters at 250 gph each. So we have 2 set ups, both with 500 gph.

You tell me are these two set ups equal filtration?

 

[Dr Joe]

Hey Bderick67...

If these filters actually flowed at thoses rates w/filter media, it wood be great to start with, but they don't so...

Let's just say they do for this...if you use the same bio-material and prefilters in both they will filter the same.. mechanics and biology are constants. As long as your flow volume & velocity rates are the same, there will be no difference.

When you put people into the equation is when things start to screw up.

Ease of maintenence usually makes the main difference...If it's hard to maintian it doesn't get done on time and the filter spec's suffer.

If one did work better (verifiable) there wouldn't be the other. Just look at all the failed filters of the past.

This goes for W/D's too.

Dr Joe

.

 

[ethnics]

i can turn my tanks over at 1x per hour, but if my bio media and filtration system is ultimate. i have no problems. gph is only a braging right to me. yes more is always better, but most importantly the media used and how much there is would be very important. but why stop ur self with a huge bio media section and low gph, or high gph and not enough media. go big on both, get an awesome pump, and an awesome setup with a nice amount of media and ur set. price difference on gph isn't that much anyway, so u might as well turn ur tank over a good amount of times.

 

[elevatethis]

Just a general idea type question...but is there a factor in filtration that takes contact time with filter media into account?

For example, with UV sterilizers, too fast of a flow causes some organisms to make it through, so you want a balance between flow rate and exposure time.

Is this similar to what goes on with water flowing through a colony of nitrifying bacteria or is it pretty much an 'instant' effect regardless of how fast the water flows through?

 

[Sunpoe]

Just a general idea type question...but is there a factor in filtration that takes contact time with filter media into account?

For example, with UV sterilizers, too fast of a flow causes some organisms to make it through, so you want a balance between flow rate and exposure time.

Is this similar to what goes on with water flowing through a colony of nitrifying bacteria or is it pretty much an 'instant' effect regardless of how fast the water flows through?

The bacteria have to take up the nutrients so they will need a specific amount of contact time.

Is it correct to assume that the below filters are equal in their ability to remove nitrogen waste from the water? :

If filter A:

Flows @ 500 GPH
and
Has a capacity of 1 gallon of media

And filter B:

Flows @ 250 GPH
and
Has a capacity of 2 gallons of media

(media being the same for both filters)

 

[Dr Joe]

Just a general idea type question...but is there a factor in filtration that takes contact time with filter media into account?

For example, with UV sterilizers, too fast of a flow causes some organisms to make it through, so you want a balance between flow rate and exposure time.

Is this similar to what goes on with water flowing through a colony of nitrifying bacteria or is it pretty much an 'instant' effect regardless of how fast the water flows through?

Yes, it's called dwell time..."dwell time: The period during which a dynamic process remains halted in order that another process may occur." in this case allowing the bacteria time to be exposed to the UV light to kill it. Or in a filter, allowing the bacteria time to breakdown the ammonia.

UV or filters are not 'instantanious', tho both do have their minimum/maximum dwell times.



</B>

The bacteria have to take up the nutrients so they will need a specific amount of contact time.

Is it correct to assume that the below filters are equal in their ability to remove nitrogen waste from the water? :

If filter A:

Flows @ 500 GPH
and
Has a capacity of 1 gallon of media

And filter B:

Flows @ 250 GPH
and
Has a capacity of 2 gallons of media

(media being the same for both filters)

No...In 'B' filter you have halved the flow rate (effectively doubling the dwell time) and doubled the amount of bio-material...If your bio-load is enough this filter is 4x more effective.

In a perfect world...Theoretically speaking.

Dr Joe

.

 

[Sunpoe]

Thanks Dr.Joe

 

[vanimate]

Yes, it's called dwell time..."dwell time: The period during which a dynamic process remains halted in order that another process may occur." in this case allowing the bacteria time to be exposed to the UV light to kill it. Or in a filter, allowing the bacteria time to breakdown the ammonia.

UV or filters are not 'instantanious', tho both do have their minimum/maximum dwell times.



</B>




No...In 'B' filter you have halved the flow rate (effectively doubling the dwell time) and doubled the amount of bio-material...If your bio-load is enough this filter is 4x more effective.

In a perfect world...Theoretically speaking.

Dr Joe

.

So a wet/dry @250gph vs. one @500gph over the same volume of media is more effective, because of the longer dwell time?

 

[johnptc]

great thread..........

my 2 cents............

at a basic level they are three types of filtration going on

1) mechanical filtration which removes the junk and debris etc from the water........makes the water clear to see thru and in principle does not alter water chemistry

2) bio filtration to convert amonia to nitrite to nitrate alters water chemistry

3) chemical filtration like carbon to remove doc ( disolved organic compounds) can make water off color ....removes chemicals from the water

flow rates do different things in each case.....

in a mechanical filter more flow is more filtering until the water pressure is so high it blows the debris thru the filter media and makes a mess

in bio filtration it more complicated as the little beasties which eat the bad chemicals need lots of oxygen and hence its a combinatiomn of flow rate... aeration and dwell time........


for carbon its mostly having enough carbon so that with medium flow ( medium dwell time) the doc's get adsorbed by the carbon.

hope thing helps ..............

After reading Johnptc's poll on filter turnover;
http://www.monsterfishkeepers.com/forums/showthread.php?t=56742
I was amazed how many people base their filtration on number on turn over.

To me this is only a part of the equation. You have to consider type of filter, type of media and amount of media, and of course bioload.

price range not a factor.

So heres a hypethetical tank set up tell me what is better.

100 gallon tank, fully stocked we are gonna go for 5x turn over rate. so 500 gallons per hour.

1 AC110 at 500gph or 2 eheim 2026 canister filters at 250 gph each. So we have 2 set ups, both with 500 gph.

You tell me are these two set ups equal filtration?

 

[Bgonz]

This is a very interesting topic. I personally believe a filter is not the only thing harboring beneficial bacteria, thus the turnover rate is not as important as the overall water circulation in the tank. I have recently completely cycled a 55 gallon community tank using no filters at all. I have two power heads for water circulation and two old pieces of driftwood and gravel. In less than 6 weeks this tank did everything that my well filtered tanks do except they dont have any type of mechanical filtration. The ammonia, nitrites, and nitrate all came and went as if done with usual filters. I currently have 6 tri-color sharks, 6 tin-foil barbs,4 convicts,4 assorted little catfish,redtail shark, and 10 giant danios. All these fish are small. I just completed my first water change and all is well. Aside from needing to vacuum the gravel often the water quality is excellent.


I agree that you generally cannot have to much filtration and flow, but i also have proven you can go filter-less and still achieve good water conditions as long as your not overstocked and over fed.


I think the best of both worlds is moderate filtration and moderate flow, and more importantly keep up on those water changes.



JMO


bob