Whats the optimal ph in urine ?

Anywhere from pH 4.5 to 8.0, depending on diet, fluid intake, etc.

I agree with Dr. Handsfield. In general, there is not an optimal urine pH. However, when you want to prevent kidney stone you may want the urine pH at either alkaline or acidic level. Give example: am alkaline urine pH, i.e. above 7, may be helpful in preventing uric kidney stone and in order to achieve that you have to eat less animal product and taking medication to alkalinize the urine.

An often-quoted range for urine pH is 4.5 to 7.8. Anywhere in that range is acceptable, and even going outside that range can be OK in some circumstances.