Add a box of Borax slowly to the skimmer while the pump is running, breaking up any clumps. Test it a few hours later (or tomorrow if you add it this evening) and add more if needed. You need to get the pH above 7.0. Once your pH starts moving, go with half box additions.

Do you have current testing results for chlorine and for CYA? We need those to really be able to advise well on bleach amounts. How high have you been taking the chlorine when you shock it? I can tell you that in your pool, each quart of 6% bleach will add 3ppm of chlorine to the pool.