Hello,
Every page has standard padding for the content. Also Revolution Slider element has standard 35px margin http://prntscr.com/cz3dnd
Add the following styles in custom CSS of your page http://prntscr.com/cz3fel
.content-page, .page-content {
padding-bottom: 0;
}
.wpb_revslider_element {
margin-bottom: 0px;
}
Regards