An ion-exchange process using a resin to remove copper ions from aqueous solution is conducted in a 1.0-in diameter column with 1.8 ft high. The flow rate is 1.5 gph and the break point occurred at 7 min. Integrating the breakthrough curve gives a ratio of usable capacity to total capacity of 0.60. Design a new tower that will be 3.0 ft high and operate at 4.5 gph. Calculate the new tower size and break-point time.