Nirjala Ekadashi Parana. The alternate Ekadashi fasting, which is the second one, is suggested for Sanyasis, widows and for those who want Moksha. When alternate Ekadashi fasting is suggested for Smartha it coincides with Vaishnava Ekadashi fasting day. Ekadashi fasting on both days is suggested for staunch devotees who seek for love and affection of Lord Vishnu.
: https://www.drikpanchang.com/ekadashis/nirjala/nirjala-ekadashi-date-time.html

