After starting iron therapy of 325 mg twice a day for iron deficient anemia, how long will it take for the symptoms of anemia to go away?

Depends. What is hemoglobin level? Do you have continuing bleeding disorder? It usually takes a couple of week for the effects of iron replacement to be apparent, if there is no ongoing blood loss. See this site for more info. http://www.mayoclinic.com/health/iron-deficiency-anemia/ds00323.