I think you might want to try that chlorine test again. FC + CC = TC. 3 gallons of 12.5% chlorine in a 16K pool should add around 23ppm of chlorine. (Which, by the way is too high for a pool with no CYA.) Take a look at the Best Guess Chlorine Chart in my signature below for the correlation between CYA and chlorine levels.

Your pH is too high. (when your chlorine is above 15ppm, your pH test is inaccurate but since your first set of numbers listed pH at 8 when your chlorine was 0, then that one should be accurate. You'll want to lower it to between 7.4-7.6 with some muriatic acid. Take a look at the following guide: Using Muriatic Acid Safely

Do you know what your CYA reading was when you closed the pool last fall?