Yes you should. If you don't put bleach in the tank over time it will start to smell like rotton eggs.
I usually put about two cups in mine because there is very little water in the tank, so it keeps it purified.
Be sure to have enough in the tank to run the pump and circulate the bleach thru out the system to the bath, hotwater heater.
When you are ready to go again, pump the tank dry add about 20 gallons of water, dump the tank again and fill it back up and you will be ready to go. If you have any bleach smell remaining you can add a couple of spoons of baking soda and it will refreshen the water.