Make sure the sand is dry...makes filling the container super easy and fast with a funnel.   Don't put the cap on until you are certain it is full enough.  Cap is a one time thing.  

Pros: Great or small umbrellas on a low wind day.  
Cons: The post does not go all the way to the ground.   The center hole stops about 4 inches into the base and about 1.5 inches from the ground.