I'm not sure it lets you vote twice in the same day. I have tried chrome incognito and chrome. If I reload and go back, it says that it already counted my vote and the number does not change on the vote tally. If there another strategy?
Clear Cookies each time and Vote as much as you want. In Chrome: History - Clear Browsing Data - check only Cookies and other browsing data. You can do it for just the last hour so nothing gets messed up.