A water tower containing $4,000$ m$3$ of water has been taken out of service for installation of a chlorine monitor. The concentration of chlorine in the water tower was $2\mathrm{.}0$ mg$/$L when the tower was taken out of service. If the chlorine decays by first$-$order kinetics with a rate constant k $=1\mathrm{.}0$ d$\_1($Grayman and Clark, $1993),$ what is the chlorine concentration when the tank is put back in service $8$ hours later? What mass of chlorine $($in kg$)$ must be added to the tank to raise the chlorine level back to $2\mathrm{.}0$ mg$/$L$?$ Although it is not completely mixed, you may assume the lank is a completely mixed batch reactor. $\_$ can this be solved using batch reactor formulaa Ct $=$ Co e$^-$kt $?$