I can't get alkalinity to drop

I recently filled my round best way 14 ft, 4ft deep pool. I have attempted to get my pools pH and alkalinity to drop, but despite adding half a gallon of Muriatic acid, I am still reading over 300ppm using my Taylor OTO test kit. When I test the PH the color seems to be always dark orange. What am I doing wrong?

Thanks in advance.
https://goo.gl/photos/txJf6pMQz7NKuCS47