Reference for Mikvaot 7:5
שְׁלשָׁה לֻגִּין מַיִם, וְנָפַל לְתוֹכָן קֹרְטוֹב יַיִן, וַהֲרֵי מַרְאֵיהֶן כְּמַרְאֵה הַיַּיִן, וְנָפְלוּ לְמִקְוֶה, לֹא פְסָלוּהוּ. שְׁלשָׁה לֻגִּין מַיִם חָסֵר קֹרְטוֹב, וְנָפַל לְתוֹכָן קֹרְטוֹב חָלָב, וַהֲרֵי מַרְאֵיהֶן כְּמַרְאֵה הַמַּיִם, וְנָפְלוּ לְמִקְוֶה, לֹא פְסָלוּהוּ. רַבִּי יוֹחָנָן בֶּן נוּרִי אוֹמֵר, הַכֹּל הוֹלֵךְ אַחַר הַמַּרְאֶה:
If there are three <i>log</i> of [drawn] water, and a <i>kortov</i> of wine fell into them, and their appearance is thereby like that of wine, and they [that mixture] fell into a <i>mikveh</i> [containing fewer than forty <i>se'ah</i>], they have not rendered it invalid [as drawn waters, since their appearance is that of wine]. If there are three <i>log</i> of water less one <i>kortov</i>, and a <i>kortov</i> of milk fell into them, and their appearance is thereby [still] like that of water, and they fell into a <i>mikveh</i>, they have not rendered it invalid [since there is still less than three <i>log,</i> of drawn water]. Rabbi Yochanan ben Nuri says: everything follows the appearance.