ok... so the dilema now is that , I cant place any objects ontop of the ground plane without them looking like they are floating.. and if I make the gap between the visible and invisible plane, to little, the bottoms of the spheres start to look sinked in again.

I can turn off collision detection on the objects to be placed on the ground, but than the spheres dont bounce off them, and effect that I'm trying to achieve is lost.

I tried changing hotpoints on the particle generator and the ground plane and no luck.