Cal Mikvah is the best way to observe the Family Purity days like Veset, Seven Clean Days, Tvila in Mikvah and all Separation days according to Ashkenazi and Sephardic related Halachot.
It will calculate all the Separation days of the Vesatot of Nidah.
Will send Emails or add to your calendar.
The calendar will also has Hebrew dates and holidays along with sunset ans sunrise time.
The App is very simple and intuitive.
You can add also your reminders to the calendar.