To calculate the amount of fluid to use per foot of rod pulled back:
Reamer Hole Diameter x Itself divided by 24
Example: 12" Reamer
12x12=144 divided by 24 = 6
Therfore you would use 6 gallons of fluid per foot of rod.
If you had 10' rods you would use 60 gallons per rod.
In theory if you had a 30gpm water pump, it would take you 2 minutes per rod during pullback.