If you've got mold in the tube, a combination of bleach solution
and tube brush may be needed. I'd think about a quick rinse, followed by scrubbing with the brush, then coil the tube up and soak it in a bleach solution. Rinse with water (three times or until you're bored holding it under the faucet) and dry thoroughly.
To prevent recurrence, as noted previously, use only water in the hydration pack. (Carbs and salts go in a more easily cleaned water bottle.) After each use, I unplug the mouthpiece and bladder plug from the tube and dry it open. You may not need to do this if you're using the hydration pack daily, but my tube is clean and still long enough after several years' use and annual trimming (to deal with stretching over the end pieces).
Originally Posted by
cyccommute
As someone who have worked extensively with chlorine and chlorine containing compounds, I can tell you that is not a material to treat lightly.
Reminds me of the middle 1970s when the California legislature considered a bill to outlaw chlorine in any product. IIRC it passed one house before someone pointed out that salt (NaCl) would also be outlawed by that bill. This kind of phobia isn't really called for. "The dose makes the poison" still applies. The soaking can be done outdoors if the bleach odor is offensive, diluting the outgassing hypochlorite to well below the damage threshold.