Should I take chlorophyll once a day to combat chronic halitosis?

Better choices. There are more effective ways to treat halitosis. It usually comes from the mouth and can be an indication of gum disease or it may be helped by scrapping your tongue. If you have not done so, see a dentist for an evaluation.
Don't mask halits fi. The source of halitosis is usually associated with gum problems. Acid reflux should also be considered.