Your manual has instructions, which are consistent with what you would find on the web:
"Sanitizing the fresh water tank- If your water has a strange odor, color or taste: •Drain the fresh water tank fully. •Sanitize the tank by adding one (1) cup (8 oz.) of plain (unscented) chlorine bleach then filling the tank with fresh water. •While filling, run at least one quart of water out of the faucet. •Fill tank until water runs out of the vent tube. •Let stand for 1/2 hour. •Drain the tank by running the faucet and allowing the bleach water to go down the sink drain. This will help clean out the gray water tank as well. •Refill the freshwater tank with fresh water, then 15 drain the tank again by removing the drain cap. •Refill with fresh water. •Run at least one gallon of water out of the faucet. •After this treatment, the water may have a slight chlorine taste and odor, but that will go away with time and is not harmful. •Remember to drain the gray water tank"
In my limited experience, you will need to flush the freshwater tank a few times. I can't compare this to the SaniTabs approach, though.
-Al