Due to your location, you may find a Reverse Osmosis service in your area. As stated, the enzyme additives have not been very successful. Sadly, that leaves you the only option: a (partial) drain and refill.
If you haven't already hit Pool School, you should..... at least that will explain in detail how you got such an astronomical CYA and how to prevent that from ever reoccurring.
Your only other option is to used only Cal Hypo shock to chlorinate your pool, it will come down slowly over time. There are also slow dissolving Cal-Hypo tabs that can be put into the skimmer in place of regular tri-chlor tabs.