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Discussion
If i have a 200l head looking to transport the water 50m in a 2.5cm diameter pvc to a 250cm rise at the end.
How tall does my head have to be to passively push the water?
Aka i have a water barrel at the barns eves trough, and want to fill 4 IBC containers stacked 2 high. In the field.
Can you share the volume flow rate you can feed? This is very important.
Oh you want more math?
On the high end 162mm/hr on my 6x12m roof would be dumped into the head
For practical purposes, Hazen–Williams equation can be used for this instance. I found head loss (which is the term that total mechanical energy that is lost due to friction; measured by length) as 2,5 meters. With the initial height of 2,5 m you mentioned; 5 meters tall of a head is needed. You can check my math if you want.
Sorry for the late response. 
Late response? I have been playing with this for 3 months lol
You kinda confirmed what i thought my head needs to be larger/ taller than my water collection. I might need to use a a jet pump which i can i was just hoping to not worry about more complicated machines