According to the article “How Bloody Tanks Got Their Name” by H.S. Ford, the location was named after an event that took place in May of 1873. US Cavalry troops were looking for a band of Tonto Apaches in the Pinal Mountains. As fighting broke out between the troops and the Indians, hundreds of Indians were slain. According to the writer, as a member of the detachment, he recalls that none were spared and the results of the fight left a name of "Bloody Tanks" located above Miami, Arizona. The Bloody Tanks Wash is also known as Miami Wash and was originally known as West Branch of Pinal Creek. Two other published sources site this event having taken place in May of 1864. King S. Woolsey, along with additional men from Prescott, were camped above the tanks. He and his men engaged Apaches he believed were hostile and lured them into the camp. “Without warning, the Woolsey party opened fire and massacred the Apaches, whose blood mingled with the water in the creek, hence the name Bloody Tanks.”
Article: H.S. Ford, "How Bloody Tanks Got Their Name