If you want tweets from a specific date range in your TweetReach snapshot report, you need to use the since and until operators:
since:YYYY-MM-DD - search only for tweets after a specific date in UTC (e.g. since:2010-03-30)
until:YYYY-MM-DD - search only for tweets before a specific date in UTC (e.g. until:2010-03-30)
Track and report on your Twitter efforts with TweetReach.
Simple, beautiful Twitter analytics for PR and marketing pros.