Answer: Yes, sadly, based on your description it sounds as though this may be artillary fungus. Unfortunately it is very difficult to remove. Bleach will not do the job -- as you have learned. One suggestions is to cover the mulch where the spores are with several inches of bark (not wood, but specifically bark) mulch. Here is some additional information about it. You may need to cut and paste the complete url into your browser to make it work correctly.
I'm sorry you are having this problem.
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