If you were to use citric acid, then the chlorine would oxidize it and produce copious amounts of trihalomethanes (THMs), especially chloroform. You most certainly do NOT want to use citric acid for lowering the pH. If you were to get half-strength (15%-16%) Muriatic Acid, then it would fume a lot less, but if you don't want to use that either, then use dry acid (sodium bisulfate). While not ideal, it is at least a strong acid you can use.