Proper gph for water filtration?

[Fishyfanatic]

The Fluval 404 has a manufacturer rating of 340 gph and is $99.99 from Big Al's. The Cascade 1200 has a manufacturer rating of 315 gph for $99.99 from Big Al's or the 1500 has a rating of 400 gph for $119.99. I know this is getting technical, but if you break it down to price per gal, the Fluval 404 is 30 cents per gal and the Cascade 1500 is also 30 cents per gal. This is of course based on the manufacturers rating. When I move the filter to the 55 gal, I'll do the gal test and see where it actually rates at. And from what i understand, it also varies depending on how much filter media is in the canister, correct?

 

[greenmaji]

The flow rate is dependent on the filter media... What types, if its used(how dirty it is), and how dense the media is(how hard it is for water to flow through the media). to get a true comparison it would be nessisary to use the same media or just the most likely used media in each.

 

[Fishyfanatic]

I'll try it both empty and full of media and see where it comes out at in regards to the gph. I was going to do that anyway, but I was just curious how much the media affected the gph. But then again, that probably differs from each filter, correct? Also, does filter floss affect the gph?

 

[greenmaji]

everything that is in the flow of the water will slow it down, to some extent. and the filter media is different in all brand filters so yes it will be different.. the highth the filter is pumping and the bends in the pipes makes a difference as well..

 

[Jchillin]

When I did the experiment, I had the following media in the Fluval:

2 sponges (8" each, side by side)
1 basket ceramic rings
2 baskets bio-balls
1 basket filter floss

Both the intake and outtake hoses are at the same length and have a slight curve as they go under the stand and in/out of the canister. I had measured the height (can't quote them now...notes are home).

The experiment was done after a PWC, when the output nozzle was free flowing and at it's maximum flow level.

 

[TomK2]

and for the record, I had the usual fluval prefilter sponges, one basket ceramic coarse prefilter rings, one basket floss, two baskets biomedia (one fluval ceramic rings, one seachem biomedia - its cheaper!) and I added 3 to four feet of 5/8 inch vinyl tubing, with two 180 degree gentle curves to send the tubing up off the filter, then down and through a wall. I got 150 gph per fluval compared to JC's 280. Extra tubing is presumed to reduce the flow, and I would think it has a greater impact than anything I would put in the basket.

To test the theory of the extra tubing causing a decrease in flow, I have a fluval on another tank, sitting below the tank with no extra tubing. I will repeat the flow measurement on that one, and see what happens.

 

[Fishyfanatic]

It looks like there are many things that are going to effect the gph test. In the 1000, I have the standard tubing length that came with the filter, a basket of filter floss, a basket of a sponge thing, a basket of ceramic rings, and a basket of AC topped with filter floss. I know the AC is not needed, but it came with the filter and I was out of ceramic rings to put in the basket. When I move it over to the 55 I'll be adding another basket of Ceramic rings in place of the AC. The test will take place Friday evening or Saturday morning during the pwc. It looks like I won't be able to move the filter over to the 55 for at least another week until Big Al's gets in the filter from back order. So this weekend I'll do the tests and report back.