I would suggest vinegar and water,it does a fine job,I use it on mine.They use a mixture of vinegar and water to clean out patients catheter bags in the hospital and long term care settings.Some people use lemon juice.The acidic content will kill alot.of germs.The idea of bleach and water and having the residue floating around in the bladder and hose doesn't sound like a mix a would like to have in my camel back.