which one gives the highest flow rate at 8ft?

[Rocky99]

which pump gives the highest flow rate at 8ft? any comments from your interpretation......

http://www.marineandreef.com/products/Iwaki_perform.jpg

http://www.marineandreef.com/shoppro/CA_Iwaki_Pump.html

http://www.riopump.net/products_pumps/RioHypr.html

below is quoted from www.marineandreef.com... certain factors to consider.... hope this useful to anybody who intends to get a return pump...

Choosing a Main System Aquarium Pump

There are three critical factors when choosing an aquarium pump: the desired flow rate, the amount of head pressure and cost.

If you want to be more exact about the degree to which the filter and plumbing will compromise the flow of the pump, you can calculate the head pressure (the calculation is provided below) and refer to the charts provided for most pumps. To see an example of this effect view the chart for the Rio Aqua Pumps (new window). Head pressure is listed as "MAX. HEAD".

Head Pressure

Generally, the head pressure is the distance from the inlet of the aquarium pump to the discharge point in the display tank. As the head pressure increases the gph will decrease.

Along with the distance from the inlet of the aquarium pump to the discharge point in the display tank, a number of factors effect head pressure:

each 90-degree bend in the plumbing will add about one foot of head due to friction

as a result of friction, each 10-foot horizontal run of pipe will add a foot of head pressure

Any time a pump discharge is shunted off, perhaps to a protein skimmer, this will also rob the display tank of flow

So, using the example of the Rio Aqua Pumps (new window), if the distance from the inlet of the aquarium pump to the discharge point in the display tank were five feet and there were two 90 degree bends in the plumbing and five feet of horizontal pipe, then the head pressure would be approx. 7.5 feet.

[blueheaven]

How come your pump is so far from your tank?

8ft of head is gonna require a damn power pump to even give substantial flow

[Rocky99]

How come your pump is so far from your tank?

8ft of head is gonna require a damn power pump to even give substantial flow

cos i got 3 elbows... the article says one elbow will increase ht by 1ft.. then top of the tank is abt 5.5ft high.... so add up will be abt 8ft......

[hamannbmw]

use soft tubing.. the head loss wont be that much