Twitter search supports date filters in search queries, so you can easily restrict your reports to tweets from a specific date or dates. There are two date filters you can include in your queries. 

• since:yyyy-mm-dd
• until:yyyy-mm-dd

You can add one or both of these date filters to any search query. For example: 

tweetreach since:2011-08-15 until:2011-08-20

A few notes about date filters: 

• Twitter stores tweets in the UTC time zone, so dates tie to UTC. If you want more flexibility over time zones, set up a TweetReach Tracker in TweetReach Pro, which will convert tweets to your time zone. 
• Dates correspond to 12:00 a.m. UTC. So the since:: filter will find tweets starting around 12:00 a.m. on the date selected, and the until: filter will find tweets up until 12:00 on that date. For example, a search for #hashtag since:2011-07-01 until:2011-07-02 will return tweets from approximately 12:00 a.m. on July 1 though 12:00 a.m. on July 2, or tweets from the full day of July 1. It will not return any tweets from July 2.
• You can include one or both filters in your queries, depending on your needs. 
• Snapshot reports access tweets from the Twitter Search API, which includes tweets from the past week or so.