Vision with Uncertain Timing

My wife felt moisture a few minutes before sunset, but did not conduct an internal check until an hour later, at which point there was blood on the checking cloth. My question is: which day is considered the day of vision, the sensation or the checking of the cloth, for the purpose of calculating the cessation of purity and the periods of separation (average, interval, and month)?

Thank you very much

Shalom Rav

Since there is doubt whether there was blood during the day, and at night there was definitely blood, everything is calculated according to the evening.