Canister filter - what's the REAL flow rate

[maxthedog123]

I know that the actual flow rate on a canister filter depends on the media used. However, I am confused about the ratings in my Fluval manual. Check out the specks on page EN-6

http://www.hagen.com/pdf/aquatic/Fluval_series5_manual.pdf

Let's take the 405 as an example: "Pump Output" is listed as 340 gph, but "Filter Circulation" is listed as 225 gph. In terms of figuring out how many times the aquarium is being filtered each hour, I am reading "Filter Circulation" as the number to use. I read turnover as 4.09x (225/55).

Opinions on which number to use? How do other manufacturers list their specs on this?

 

[Mgamer20o0]

you need with media.... the 404 is like 187gph with media.... unless they put in a bigger pump for the 405 it should be the same.

 

[maxthedog123]

I think that's what "Filter Circulation" is supposed to be. ("Pump Output" is higher.) It lists Filter Circulation as:

105: 85gph
205: 110gph
305: 185gph
405: 225gph

http://www.hagen.com/pdf/aquatic/Flu...es5_manual.pdf Page 6.

 

[Mgamer20o0]

225gph but it doesnt say with media does it?

 

[KnaveTO]

Yeah I try to find the gph with media numbers. Sometimes you can find them in the packaging or the manufacturers website and some stores display the info on that on their websites as well.

 

[Rbishop]

Cut whatever they claim by 50%

 

[Weezer]

Cut whatever they claim by 50%

Wow, I thought it was more like 25 %, i better get 2 more Mag 350's for the 80........

 

[mcox3]

you can always get a flow meter... but they only measure to something like 250gph...

 

[PDX-PLT]

I'm guessing "pump output" is the theoretical maximum flow on an unrestricted pump - no filter, no outlet pipe. They have to publish this for marketing reasons, as the consumer is trained to believe the bigger this number, the better. "filter circulation" is closer to the flow you actually get.

Note that higher flow isn't always better. While it may help with mechanical circulation, if the velocity through the media is too high, it impairs biological filtration - the bacteria don't have a chance to do their job.

Perhaps they quote the "pump output" number to make it look good marketing-wise, but they design the actuall filter flow for good biological filtration.

 

[Rbishop]

Wow, I thought it was more like 25 %, i better get 2 more Mag 350's for the 80........

Should I post my "C" series 360 review......