high Alkalinity -420

[seachelle1969]

Ok here we go. New pool,only up for a week .Added 2 chorine tabs to floater and 1 to skimmer . Had water tested, showed very low clorine level almost at zero. Alkalinity was 420 HIGH along with hight PH level. Added a gallon of MURIATIC ACID. I followed by adding Ph- a shock treatment and a stabalizer . New readings 2 days latter , LOW CHLORINE ( ALMOST ZERO) Alkalinity 300 and high PH.
Ok Now i have added another 1-1/2 gallons of MURIATIC ACID levels are still hight not sue what the number is , i havent taken it to the pool store to be tested again , but strips are still reporting ALKALINITY as high, PH as high and CHLORINE as ZERO . So my question is , what is causing the levels to NOT to drop, and at what point do you stop adding MUriatic Acid . Any advice would be great . The pool is a above ground 24x52 round. I would like to add teh water is just beautiful crystal clear . Thanks