A groundwater is to be softened by split$-$flow ion exchange with the exchange resin on the sodium cycle.

The well water flow rate is $75$ gpm$,$ the hardness is $225$ mg$/$l as CaCO$3,$ the desired hardness is $50$ mg$/$l

as CaCO$3,$ the resin removes $350$ meq$/100$ gm on a dry weight basis at an allowable breakthrough

$($leakage$)$ of $2\mathrm{.}5\%$ Co$,$ and the resin moisture content is $40\%.$ The allowable breakthrough time is $10$

days. Determine the pounds of resin required on both a moist and dry basis.