After a few weeks of trying to get CYA down so I could slam at a reasonable FC, I spoke with Cholrox people (1-800-SOS POOL).
They informed me that CYA was not really a problem, that mustard algae is chlorine resistant, and suggested using XTRABLUE algaecide. Over night my algae is nearly gone.
I highly recommend this product. I'm kind of surprised that I have seen no mention of algaecides in my previous threads regarding this problem.
By the way, the BIOactive CYA reducer was not effective for me. I could have saved that $50 if I'd talked to these folks first. In all fairness to the forum, the consensus was pretty negative on the BIOactive stuff, but I thought it was important to get the cya down so I tried it as a last resort.