Last results post:
Since my extended, proper shock in October - November 2014 I have maintained the 15% of CYA level for FC in the pool. I have had no further indications of any algae. I conclude that the multiple short shocks I had done prior to then (1) had never actually cleared the algae and (2) the current regimen is indeed effective at controlling it. Unless something breaks down this will be my final results post for this necro-thread.
Thanks, all.