Are these really necessary?
Although I've never used this product I question its usefulness. There are definitely less expensive alternatives that do the same job. I mix ¼ cup of Listerine (any mouthwash will do) with ¾ cup of water and shake it up in the bladder. They I draw the fluid from the mouthpiece to clean out the tube and mouthpiece. The next step is to drain any remaining fluid from the bladder but DO NOT rinse out any residual mixture. You can do that right before you use the bladder the next time. Store the bladder in the refrigerator until next use. Ive been doing this for years and have never had a mold issue. Plus, if you forget to rinse all the fluid before you use it next, your breath will be minty fresh! ;-).