Cotinine is detectable in blood for at least several days after exposure to tobacco smoke. Depending on how much you smoke, the level of cotinine in your blood will reflect a nonsmoker level in 7 to 10 days. The nicotine test that offers the longest detection window is a hair follicle nicotine test. These are rarely administered due to their expense, but they do exist.
High pH is NOT always BAD! But, high pH is NOT always GOOD, either! The recommendation that swimming pools should be operated at pH levels between 7.2 and 7.6 is almost universal. This recommendation is enshrined in generations of pool books and literature. It's embedded in many state swimming pool codes. Unfortunately, for most swimming pools, it's also far from ideal.
You should wait to enter the water until after all treatment checmicals have been fully dispersed and dissolved in the water. Also, swimmers should not enter the pool unless the pH is in the range of 7.2 and 7.8 and the available chlorine level is in the range of 1-3 ppm when tested with a pool test kit or test strips. Once levels are within the range, you are free to swim.