hourglass of lights - fluid particles system

Sandglass filled with a fluid particles system. Each particle is an object defined as a point of light. 500 particles are used here.

Noted that the repulsion factor is max and interaction radius is far higher than the defined particule size. This is to lower the particules ' concentration.

Blend file is here:
https://docs.google.com/open?id=0B2BWubg0Qrg4dzhGVHhHSnZsS00

Let me know you comments.