Closed loop / head pressure question

[justiceprevails]

I'm installing a closed loop on my 225 that I'm setting up. The input is on the bottom of the tank and returns on the side. Originally I was going to put the pump on a shelf as high up under the stand as possible to reduce the head pressure and get max flow rate. But then I began to think about it and I don't think it matters if I put on a shelf or on the tank stand floor. The water will fill the whole system due to gravity (even without a pump installed). So won't I have zero head pressure (other than the resistance of the pipe walls and elbows? In other words if the pump specs states 700GPH at 1' or 600GPH at 3" etc... I shout be getting close to 700GPH. Thinking wrong?

 

[ArminTamzarian]

If what they taught me in fluid dynamics is correct, so are you!

 

[tonysdiscus]

sweet!!!

 

[WarDaddy]

you are correct, there is very little to no head pressure in a closed loop. All the pressure is from friction and turns.

 

[justiceprevails]

Thanks to all