True GPH of the Fluval FX6

[Dom90]

Ok so what is it? Some sites I have seen say 563, others say 900. The Fluval website says Pump output 925 GPH but flow rate 563 GPH. I'm so confused.

 

[LeoDiaz]

563 is closer the 925gph is before any head pressure is applied.

 

[Dom90]

What is head pressure?

 

[LeoDiaz]

What is head pressure?

Every foot/inch the pump has to pump water to get to the tank adds pressure to the pump decreasing flow speed.

 

[Dom90]

Oh I see, so 900 is like the "horsepower" of the pump lol.

 

[LeoDiaz]

Oh I see, so 900 is like the "horsepower" of the pump lol.

In a way. If you see specs of aquarium pumps you can see they show how the flow decreases Ex look at this pumps(click on more info)

 

[SnyperTodd]

563 is closer the 925gph is before any head pressure is applied.

No, there is no static head for a canister filter to overcome. The canister filter is a sealed system. As the water comes into the filter, it pushes the water already in the filter back out. The only thing the filter has to overcome is the friction of the water moving through the tubing.

More than likely, the difference in flow rates is between an empty canister and a loaded one.

 

[LeoDiaz]

No, there is no static head for a canister filter to overcome. The canister filter is a sealed system. As the water comes into the filter, it pushes the water already in the filter back out. The only thing the filter has to overcome is the friction of the water moving through the tubing.

More than likely, the difference in flow rates is between and empty canister and a loaded one.

I'm not sure but there still be some pressure? I'm going to email fluval and see what there explanation. I heard people say canister loose flow from head height.

 

[SnyperTodd]

I'm not sure but there still be some pressure? I'm going to email fluval and see what there explanation. I heard people say canister loose flow from head height.

The height doesn't matter at all in a sealed system like a canister filter. You could put the filter in your basement and have the tank on the roof, and the pump in a sealed system will still only have to overcome the frictional losses of the tubing, which will be slightly greater with longer hoses, but still no static head.

In your example in the link in post #6, those pumps are designed for use in an open system (like a sump), where the water coming in does not assist the water going out. That's when you need to factor in head.

Edit: One way you can show this is to set up a canister filter and set up a pump (from your link above) in a bucket. Prime both, get them both flowing, then stop them. Check the water level in the discharge hoses. The distance from where the water level settles to where it's discharged is your static head. On the canister, it'll be right up to the top- the pump only has to overcome a little friction to get the water moving. On the pump in the bucket, it'll be at the waterline in the bucket. That pump has to lift that water all the way to the end of the hose.
Does that make it clearer?

 

[LeoDiaz]

The height doesn't matter at all in a sealed system like a canister filter. You could put the filter in your basement and have the tank on the roof, and the pump in a sealed system will still only have to overcome the frictional losses of the tubing, which will be slightly greater with longer hoses, but still no static head.

In your example in the link in post #6, those pumps are designed for use in an open system (like a sump), where the water coming in does not assist the water going out. That's when you need to factor in head.

To bad I don't have a basement or can get on the roof to prove your claims... Lol

 

[SnyperTodd]

While I have a fairly solid understanding of this area of fluid dynamics, my education and background is more in hydraulics and positive-displacement fluid pumps. Jsigmo has more experience and a better grasp on this particular subject matter than I do. He can be of more help.

 

[BDpups]

SnyperTodd is correct and explained it as I understand it as well.

I would think the 563 GPH maybe when it is full of media. The 900 GPH is when it's empty.

What size tank are you wanting to put it on and what stock Dom90 ?

 

[Dom90]

SnyperTodd is correct and explained it as I understand it as well.

I would think the 563 GPH maybe when it is full of media. The 900 GPH is when it's empty.

What size tank are you wanting to put it on and what stock Dom90 ?

80 gallons with 7 or 8 goldfish possibly, So I need the overfiltration lol.

 

[Jsigmo]

SnyperTodd and BDpups are right.

(Why does this remind me of this scene)?

With the system being sealed, there is no "static head" to be overcome. The pump does not have to "lift" the water at all.

Here's a simple experiment you can perform to demonstrate this concept:

Simply fill a few feet of clear tubing with water, leaving a few inches empty at both ends. This works best with tubing that's not too small in diameter because you avoid surface tension problems. Airline tubing may work OK, but it will be better with something like the tubing you use for a canister filter.

Now, let the tubing droop down as you hold the two ends up near each other. You will see that the water level at both ends of the tubing stays the same. Sometimes you hear people say "Water seeks it's own level." That's what they're talking about.

You see this principal used to get things to be level on construction sites, etc. They sell kits that have two sections of clear tubing with fittings to mate to the male and female ends of a garden hose. You fill the garden hose (of any length) with water such that it fills up into the clear tubing sections on the ends. Then, you can place one end at one point that you're using as your reference, and line up the water level with that reference point. Now you can move the other end of the hose anywhere you want, and check to see if something is at that same level.



Anyhow, if you were to cut your section of tubing in half, and place a canister filter with its pump in the middle, having one half connected to the inlet and the other half connected to the outlet, but don't run the pump, the same thing will be observed.

If the canister and tubing is mostly filled with water, the water level will be the same for both the "inlet tube" and the "outlet tube". This must be so because gravity pulls all of the water down to the lowest possible position it can occupy. There is no differential pressure across the canister pump. It sees the same "weight" of water at the inlet as the outlet.

Further, if we submerge the two ends of the tubes into a container of water above (or even below) the position of the canister, then the pressure is kept absolutely equal on both the inlet and outlet of the canister.

So the only resistance the pump of a canister filter needs to overcome is the friction loss in the tubing and within the canister due to the media and any crud that's built up in there.

Now, you don't want to discount the effect of the friction loss in the tubing. It's a very real resistance that must be overcome. So if you have a long length of tubing between the canister and the aquarium, it will resist the flow of water more than if you have a short run. Also, if you use skinny tubing, that will create more friction loss than fatter tubing.

But the height of the canister with respect to the height of the aquarium won't actually affect things at all.

When I was a kid, I had one of these:



It wasn't that exact set, but I'm very glad to see that this is still being made. Playing with that when I was a little kid, back in the mid 1960s, instilled a "gut feel" for all of this in me at an early age. That "feel" for all of this has been a tremendous help to me over the years both for hydrodynamics as well as electronics because very similar principals are involved.

I highly recommend everyone get one of those for their kids. It is truly one of the most fun, yet educational toys I've ever seen. Then, after you've played with it for a few weeks, maybe let the kids actually have a turn with it, too!

 

[BDpups]

80 gallons with 7 or 8 goldfish possibly, So I need the overfiltration lol.

An FX6 would be fine then.

 

[Dom90]

Anybody own a FX6? What are the two dials on top of the canister for, or what do they do?

 

[Jsigmo]

Go here:



Scroll to the bottom, and click on instruction manual.
It'll download a PDF version. Pretty fancy unit!!

It looks like those dials are just reminder indicators you can set to point to the day you last did maintenance.

 

[LeoDiaz]

This is wat I got from fluval.

We thank you for taking the time to contact us.

Please tell me where you are seeing the 900gph information as I only see the information below which is listed on our website:
"Fluval FX6 is a high performance canister filter with many outstanding features designed to make aquarium fishkeeping easier and more convenient than ever.

This super capacity yet compact canister filter processes and circulates 2130 litres (563 US gallons) of water every hour and has an astounding media capacity that produces cleaner and healthier results.

Filtering material can easily be placed in a removable stack of media baskets which is at the heart of Fluval's multistage filtration. The baskets are precision-engineered to eliminate water by-pass, making filtration more efficient.

The baskets can hold a total of 5.9 litres of media and can be stacked in the precise combination of layers that will work best for your aquarium. Each one is lined with a foam insert for effective mechanical pre-filtering. Instant-release T-handles let you lift and separate the baskets quickly and easily, making routine maintenance simpler.

Fluval FX6 also features Smart Pump Technology, which provides optimal filter performance. This advanced technological feature employs an electronic circuit board that continually monitors the pump. Impeller speed and force are constantly measured to ensure powerful output and energy efficiency. It also manages the filter's self-starting feature and evacuates air that may enter or build up within the filtration system. On a 12-hour cycle, the pump will pause and allow trapped air to escape, ensuring the best filtration efficiency at all times.

Only 54 cm (21") in height, Fluval FX6 fits under most aquariums.

Key Features:

Multi-Stage Filtration produces healthy aquarium water
For fresh and saltwater aquariums
Features Smart Pump Technology for optimal filter performance, efficiency and management
Advanced motor technology provides better performance and reliability while consuming 10% less electricity
Click-Fit AquaStop Valves allow fast setup and leak-proof maintenance
Valves are positioned at 45 degree angles and rotate for easy installation
Self-starting filter-just add water and plug in-Smart Pump Technology will do the rest
Monthly maintenance indicator allows you to remember the date of your last filter maintenance/water change
Heavy-duty Anti-Clog Telescopic Strainer ensures continuous flow
Multi-Directional Output Nozzles can be adjusted to create specific water flows
Purge Valve with Drain Hose for easy maintenance and flushing of the canister
Water change feature eliminates need to carry buckets of water-simply attach appropriate hose to the output-Smart Pump Technology will do the rest (Kit sold separately)
Flow rate: 2130 litres (563 US gallons) per hour
For aquariums up to 1500 litres (400 US gallons)


Thank you,
Caren Arsenault
Customer Service
Rolf C. Hagen (USA) Corp.

 

[Dom90]

Pump output: 3500L (925 US GAL)
Pump output: 3500 L (925 US GAL)
Pump output: 3500 L (925 US GAL)

 

[LeoDiaz]

Send them the link lets see what they say.