Skandapurana 16.284.2

16.284.2

yatra prāptavatī kāmaṃ sukanyā varavarṇinī ..
saraḥsnānaprabhāvena tena kanyāsaraḥ smṛtam ..
tatra snātā śubhā nārī tṛtīyāyāṃ viśeṣataḥ .. 2 ..

Where Sukanyā, of fair complexion, obtained her desire / through the power of bathing in the pool; therefore it is known as Kanyāsaras. / A virtuous woman who bathes there, especially on the third [lunar day], // 2