You need to be extremely cautious when using bleach for items in your tank. Even the slightest amount of residue left behind can kill an entire tank.
If you're going to do it, use a 20:1 ratio of water to bleach, and rinse rinse rinse. And when you think you got it all, rinse some more.
Elbow grease is the best method IMO
. White vinegar, also at a 20:1, will work as well and is much more safe than using bleach.