You don't have to drain ....... lots of people just live with the high CYA and just run higher chlorine levels to compensate for it. That works, too. At this point in the summer, you might just want to leave it. Some pools lose a lot of CYA over the winter. You may just want to wait and see where your CYA is in the spring when you open and do some partial drains at that time if it is still high.

http://pool9.net/cl-cya/

I am also a little concerned that you may not be doing the CC test correctly. It is pretty unusual to get that kind of a result. Can you explain your steps that you are following to do the FC and CC test so we can verify that you are doing it properly?

How does your water look?

How consistently are you adding the bleach each night to keep the pool at shock level? It has to be done consistently. Doing it every few days isn't gonna work.