pH is the measure of how acidic or alkaline (basic) a substance is. Urine with abnormally high or low pH can contribute to the formation of certain types of kidney or bladder stones. In dogs, urine pH should be between 7 and 7.5. In cats, it should be between 6.3 and 6.6. Potassium citrate can be used to raise the pH, making it more alkaline (basic). Ammonium chloride or DL‑methionine can be used to lower the pH, making it more acidic.