ismocan
Hi
The min-height value is auto and varies different with screen sizes and based on the article content.
I check some of articles on site but there is no such blank space.
You can give me the link of page on which you have this issue. or add this code in custom.css file to override the style
.t3-content, .t3-main-content {
min-height: 100%!important;}
Regards