Mishnah Zavim 1:5: If he saw one [discharge] as profuse as three [discharges] lasting as long as it takes to walk] from Gad Yavan to Shiloach, [an interval] which would be sufficient for two immersions [in the mikveh] and two dryings, he is a full fledged zav. If he saw one [discharge] as profuse as two, he renders unclean anything he sits in on or lies upon and he requires immersion in running water but he does not have to bring a sacrifice. Rabbi Yose said, They did not speak of one [discharge] which was profuse [enough to make him a full fledged zav], unless there was enough [volume] to equal three.

ראה אחת מרבה כשלש, שהיא כמין גד יון לשילוח, שהן כדי שתי טבילות וכשני ספוגין, הרי זה זב גמור. ראה אחת מרבה כשתים, מטמא משכב ומושב, וצריך ביאת מים חיים, ופטור מן הקרבן. אמר רבי יוסי, לא אמרו אחת מרבה אלא אם כן יש בה כדי שלש:

Mishnah Zavim 1:6: If he saw one [discharge] during the day and one at twilight, [or] one at twilight and one the next day, if it is known that part of the sighting [the discharge at twilight occurred] during the day and part was the next day, he is certain with regard to a sacrifice [that he must bring one as a zav] and with regard to uncleanliness [he is unclean]. If is was doubtful if part of the sighting was today and part was the next day, there is no doubt regarding his uncleanliness, but there is doubt regarding his sacrifice. If he saw [discharges] on two [consecutive] days at twilight, there is doubt regarding his uncleanliness and his sacrifice. If he saw one [discharge] at twilight, there is a doubt regarding his uncleanliness.

ראה אחת היום ואחת בין השמשות, אחת בין השמשות ואחת למחר, אם ידוע שמקצת הראיה מהיום ומקצתה למחר, ודאי לקרבן ולטמאה. אם ספק שמקצת הראיה מהיום ומקצתה למחר, ודאי לטמאה וספק לקרבן. ראה שני ימים בין השמשות, ספק לטמאה ולקרבן. אחת בין השמשות, ספק לטמאה: