I wouldn't reccommend bleach to combat mould in your dreads. Lots of herbs and essential oils are anti-fungal and would help prevent/get rid of mould. Tea tree, rosemary, peppermint and thyme have anti-fungal properties, are easy to find and are usually fairly inexpensive.
prevention is the best measure, keep dreads dry (make sure they are dry after being wetted before putting them up or putting them under a hat) get as much sun as possible
I make sure I don't get mould by squeezing excess water out on the bath then I wrap it up in a towel for and hour and hair dry it for an hour. If you have the patience to dry it properly you shouldn't get mould. Bleach is good for mouldy toilets but suicidal for dreads
sew them together in the roots I have done that to many of my dreads. Some of them are trying to combine on their own, but i rip them apart....well at least i did that until now
