# Over filtrate



## CraigStables (Oct 5, 2003)

Is it possible to over filtrate a tank?

I've just got two 2000 Gal/hour pumps for really cheap and wondering if I should use them both or just one and sell the other. They will be going on a 150 Gal tank, with a huge wet/dry.


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## ttldnial (May 14, 2003)

10x filtration is recommended for mechanical filters (HOB,cannister).
wet/dry filters are NOT meant for a high flow rate.

Just one 2000 gal/hr pump could be too much.
I'm not sure...Perhaps if you could get the pumps 'head' rating it would tell us more.

I have a 150 gallon, with wet/dry.
I bet with my head height I only get about 600 gph.


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## icepick36m (Feb 19, 2003)

The more filtration the better...as far as I'm concerned.


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## Dr. Giggles (Oct 18, 2003)

For a wet dry you want a pump 5 times the size of the sump was built for. For example a sump for a 125 gallon tank an ideal pump would be 625 GPH. There is a reason why they call it a trickle filter.


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## acehigh (Mar 5, 2004)

Hi Mate!

Once your tank has cycled, and no traces of ammonia or nitrite are detected your filters used are filtering your tank. No more bacteria will grow as there is no more food for it. This means any more filters added efectivly only act as an expensive power head. You could use one to add any additional mechanical filtration if needed. I have an extra filter I stuff full of wool, I also use it to add aditional things when needed, water softner pillow, nitra zorb.


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## Peacock (Feb 23, 2004)

there is no such thing as over filtration in my book.










also, GPH doesnt mean anything.. the more GPH does not mean the better the filter.


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## acehigh (Mar 5, 2004)

Sorry Mate!

Ignore my last, just realised you are on about the pump, flow rate on your wet & dry. Not actualy adding more filter..

Cheers!


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## CraigStables (Oct 5, 2003)

Yeah I understand that the limiting factor would be the size and quality of the wet/dry, but I know that mine is large enough to handle 4000 Gal/hour.

Im more wondering if I had 4000 Gal/hour filtration on the one 150 Gal tank would it be too much, would I be losing the beneficial bacteria during filtration?!

Cheers


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## 3781 (Mar 24, 2004)

Hi Craig,

You can definately wash off your bacteria with a high flow rate. Biological filtration generally likes a slower flow rate anyway.

If you must use a big pump, then throttle the output with a valve. Do not restrict the intake side with a valve. This can damage your pump.

Also, flow rates that fast in a small tank would be more suited for salmon, that piranhas.









Best Wishes,

<*(((((><


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## PiranhasaurusRex (Feb 23, 2004)

Are those submersible pumps? I'll take one off your hands if u just decide to use one.


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## CraigStables (Oct 5, 2003)

PiranhasaurusRex said:


> Are those submersible pumps? I'll take one off your hands if u just decide to use one.


 they can be used either as a submesable pump or inline. Im from the UK though mate, so with shipping, etc. ontop it wouldnt be very cheap for you, easier to get one from in the US!


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## Noe (Aug 22, 2003)

It should be 10x filtration is recommended for mechanical filters.
But you could never have to much filtration in your tank. Too much filtration will not hurt your P's.


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## Peacock (Feb 23, 2004)

[email protected] said:


> Hi Craig,
> 
> You can definately wash off your bacteria with a high flow rate. Biological filtration generally likes a slower flow rate anyway.


 No you cant.. you Cannot Wash off bacteria with a high flow rate.. they are extreamly "sticky"..

gallons per hour does not = better filtration.. only with mechnical.. but Biological filtration is only greater with an increase of surface area. not gallons per hour.


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## CraigStables (Oct 5, 2003)

Peacock said:


> No you cant.. you Cannot Wash off bacteria with a high flow rate.. they are extreamly "sticky"..
> 
> gallons per hour does not = better filtration.. only with mechnical.. but Biological filtration is only greater with an increase of surface area. not gallons per hour.


 Thats what I thought!

Im going to use them both, but set up another wet/dry so one filter for each wet/dry system. That way I'll be doubling the amount of surface area I've got!


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## Puma (Jan 27, 2004)

just keep in mind that doubling surface area does NOT = doubling nitrifying bacteria....necessarily.

if, for example, you had a 10 gallon tank with a single betta.....you would not "gain" anything in the way of biological filtration by upgrading from one powerfilter to two, since there simply isnt adequate food source for the bacteria.....this situation often is the source of argumentation for the "bio wheel vs. the aquaclear sponges" in those type of debates.....while the bio-wheel may be _capable_ of colonizing more bacteria, that doesnt mean that it _will_....blah blah, sorry.

in a heavily stocked tank though, go for it!


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## Peacock (Feb 23, 2004)

nice one puma


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## acehigh (Mar 5, 2004)

I do not run a wet & dry, but would it not be limited to the amount of water the drip plate lets through?


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## PiranhasaurusRex (Feb 23, 2004)

acehigh said:


> I do not run a wet & dry, but would it not be limited to the amount of water the drip plate lets through?


 You can always add more holes or make your holes bigger if the drip plate is the bottle neck.


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## DonH (Jan 25, 2003)

You do not want to increase the flow of water going to the bio media than what the sump was built for. It defeats the purpose of it being a wet/dry or "trickle" filter.

If it seems like it's bottle-necking at the drip plate or overflow, than you need a smaller pump or buy a larger wet/dry unit.


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## PiranhasaurusRex (Feb 23, 2004)

DonH said:


> You do not want to increase the flow of water going to the bio media than what the sump was built for.


 ??? How would you increase the flow to more than what the sump was designed for??? Are we talking about DIY wet/dry here?


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## DonH (Jan 25, 2003)

PiranhasaurusRex said:


> DonH said:
> 
> 
> > You do not want to increase the flow of water going to the bio media than what the sump was built for.
> ...


Smaller sumps only hold a small volume of biomedia so increasing the flow via larger overflow, larger pump, and (like you said) drilling extra, larger holes will allow more flow into the sump. This will change the capacity that it was designed for. A larger sump will hold more volume and would have a larger surface area over the drip plate, therefore, even with the same flow rate, it will still have a "trickling" effect as opposed to a monsoon. It's all about the contact time that water has with the surface area of the biomedia.


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## Peacock (Feb 23, 2004)

DonH said:


> PiranhasaurusRex said:
> 
> 
> > DonH said:
> ...


im going to take a shot.

DonH, Do you believe Bacteria have a hard time "catching" food out of flowing water?

EDIT- woohoo Post # *666*


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## Peacock (Feb 23, 2004)

Shot was fired DonH...

Turn it around!


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## DonH (Jan 25, 2003)

Peacock said:


> DonH, Do you believe Bacteria have a hard time "catching" food out of flowing water?


 Retention time has nothing to do with the "difficulty" nitrifiers have with catching food.

Read this!

It's for koi ponds but the principles still apply.


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## Peacock (Feb 23, 2004)

ill check it out and get back to you tomarrow.


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## squiggly (Mar 21, 2004)

Don, why would a longer dwell time be more effiecent then a higher flow rate? If both spend the same amount of time in contact with the media.


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## Death in #'s (Apr 29, 2003)

dam peacock u are the filtration king


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## DonH (Jan 25, 2003)

squiggly said:


> Don, why would a longer dwell time be more effiecent then a higher flow rate? If both spend the same amount of time in contact with the media.


 I don't understand your question...

How can a higher flow rate through the same surface area increase dwell time (which is the amount of time a water particle is in contact with the biofilm)?


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## squiggly (Mar 21, 2004)

If the water spends 10min per hour in the filter for low flow and high flow would spend 1 min but moves through the filter 10x per hour it would spend the same amount of time in contact with the media. Correct?


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## DonH (Jan 25, 2003)

squiggly said:


> If the water spends 10min per hour in the filter for low flow and high flow would spend 1 min but moves through the filter 10x per hour it would spend the same amount of time in contact with the media. Correct?


you have it the wrong way...

Using your example: If a water particle travels under low velocity has a dwell time of 10 minutes, then the same water particle travelling under high velocity (in your case 10x the velocity) would have a dwell time 1/10 of the original. NOT the same dwell time (assuming the volume of the filter is the same)...

It's like a car (water particle) going through a tunnel (the filter). If the car is going 35 mph through the tunnel and it takes 10 minutes to pass the tunnel (dwell time). How long does the car stay in the tunnel if we double the speed to 70 mph? Half the time (5 minutes). Right?


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## squiggly (Mar 21, 2004)

I am not saying that each pass the dwell time will be equal. But that the higher flow rate will cause the water to be in the filter 10 more times in a given time period. And hence the water will be in contact with the media the same amount of time. (10 minutes = 1 minutes (10)) So the water will spend the same amount of time in contact with the bio-film.


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## DonH (Jan 25, 2003)

I think you are comparing 2 different aspects of filtration. Retention time vs turnover rate. The link I provided states that both are necessary for efficient filtration.


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## squiggly (Mar 21, 2004)

Thanks Don! I went back and reread it severals times and now see what I was trying to understand.


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