A different aquarium should contain 15,000 liters of water when filled correctly. It will overflow if it gets to 17,600 liters. One day there is an accident and the tank cracks in 4 places. Water flows of of each crack at a rate of 1/2 liter per hour. And emergency pump can re-fill the tank at a rate of 2 liters per minute. How many minutes must the pump run to replace the water lost each hour?