This is another one of those areas where stuff works differently on different people.When bleaching dark hair, it usually goes through an orange or 'ginger' phase before it gets to blonde. Try the normal strength bleach first; if that doesn't do it for you, and if it's fine with your skin, you can go on to the extra strength stuff. You may have to experiment with how long you leave it on, too.
There are a few other options, too; you could get it waxed if it really bothers you, or try some sort of home hair removal stuff like Nad's or (I think it's called Surgi-Cream?).
Or you can learn to like it. 
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Laurel Lemming
Scarleteen Advocate
"And when the answer that you want/Is in the question that you state/Come what may..." - Coheed and Cambria, "Blood Red Summer"