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.
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)Oh I see, so 900 is like the "horsepower" of the pump lol.
563 is closer the 925gph is before any head pressure is applied.
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.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.
To bad I don't have a basement or can get on the roof to prove your claims... LolThe 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.
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 ?