I'm pretty new at this stuff myself -- but I did deal with some mustard algae earlier this summer -- and with the help of this forum -- got rid of the darn stuff.

Are your chlorine numbers staying that high each time you check it? I cannot answer about the pH, but according to the knowledge I've gotten through the forum regarding treatment of algae -- BLEACH BLEACH BLEACH

Keep it at shock levels while checking it (3X a day if possible). I also left my pump running 24/7 while dealing with this (but I always keep it running 24/7)

Have you checked some of the other algae threads (some have pictures -- which helps (did me) you realize you will see the end of the algae!) You might want to check those out.

Hopefully, if you shock the heck out of it, it should be okay in a few days! Sounds like you're on the right track though.