Sandbags/Balast for light stands

[ipodsandguns]

Today I learnt I need some.

Suggestions and links to proper ones?

IV had the idea of just using ankle weights strapped to the bottom of the stand.

 

[planetx]

What I use
http://www.calumetphoto.co.uk/eng/product/calumet_25_lb_11_3kg_sand_bag_empty/pi3025