I am amazed at how these "Charging" pumps seem so undersized compared to what I am used to seeing. At my plant we call the "Charging Pumps", Makeup Pumps. These babies can both each give me 170 gpm if I have them piggybacked to my LPI pumps at 2750#. I can get about 150 GPM if I have them sucking off my makeup tank. My HPI pumps kick in at 1600# if they are straight off of my Borated Water Storage Tank, 1850# if they are piggy backed as well on the LPI. These HPI pumps are good for about 800 gpm each.