There is no set number of days when ovulation test paper is weakly positive to strongly positive, and it is generally considered to be of little significance to have a weakly positive ovulation test paper.
The ovulation test measures the peak level of luteinizing hormone (LH) in the urine. It is usually taken from around day 11 of the menstrual cycle and is taken once a day. A weak positive test usually indicates that the Luteinizing Hormone (LH) in the urine has not yet peaked, meaning that the follicle has not yet matured, or that ovulation has occurred more than 48 hours ago.
There is no fixed number of days from a weak positive to a strong positive ovulation test, and this time is greatly affected by individual differences, so it is not possible to generalize.
Clinically, it is recommended to use ovulation test paper in combination with ultrasound examination. When the dominant follicle reaches 18-20mm in diameter and the LH test paper is positive, 80% of ovulation will occur within the next 24 hours.