HTML --> EPUB - ugly spaces between lines

Hello :).
For some reason Calibre creates these ugly spaces between lines if i convert from html (made from pdf) http://prntscr.com/8n1ggi

This how it looks on kindle http://prntscr.com/8n1gmu

And this is reflowed pdf by k2pdfopt and then to epub http://prntscr.com/8n1ins

How to push Calibre to make epub looking like this from k2pdfopt?

Greetings.

EDIT:
I have saved epub from sigil from html without making any improvements It looks like this
http://prntscr.com/8n202v
And this is Calibre same without any options and strange "enters' between lines.
http://prntscr.com/8n1ggi
How to force calibre to not doing this ugly spaces? Thanks