Running Vim inside tmux* with space-vim-dark colour scheme requires a bit of tweak. This is probably because the scheme requires 256 colors. Fixing this requires updating both the tmux and vimrc configuration files.
Tmux config file:
set -g default-terminal "screen-256color"
Vimrc config file:
colorscheme space-vim-dark
let &t_8f = "\[38:2:%lu:%lu:%lum" let &t_8b = "\[48:2:%lu:%lu:%lum"