I have to wait a week to retest my CYA. My water is clear. My Ch is 175. My FC is 4. I have only had my test kit for a few days. My other test kit before I got my Tf100 showed my Alkalinity was normal.
For now, I would simply monitor your pH (of course, keeping your FC up is job #1).
If your pH goes to 8.0, adjust it down but do so using the process for lowering TA. That article is in Pool School and it will allow you to lower your TA down as well as reduce your pH. Post back if you have a question on that TA lowering process.
Are you positive that TA was 170 to 180. The following is from Extended Test Kit Instructions.
Sometimes a static electric charge can build up on the R-0009 dropper bottle tip, causing the drops to be smaller than usual and making the test read higher than actual. You can prevent this by wipping the tip of the dropper bottle with a damp cloth or tissue before you start and after each drop.
Hold the dropper bottles vertically and squeeze gently, so that drops come out slowly and seem to hang on the tip of the dropper bottle for a moment before falling.
Are you swimming in your pool now? If so, I'd just let the pH drift back up again, and again lower it with MA. You don't need to hit a precise number with TA. My TA is above normal in my pool, but my pH sits at 7.6 and doesn't drift, so I live with the higher TA number.