A bankrupt chemical firm has been taken over by new management. On the property they found a 20,000 m3 brine pond containing 25,000 mg/L of salt. The new owners propose to flush the pond into their discharge pipe leading to the Atlantic Ocean, which has a salt concentration above 30,000 mg/L. What flow rate of fresh water (in m3/s) must they use to reduce the salt concentration in the pond to 500 mg/L within one year?