[ReefLady]

Here's what we did - I hope I can explain this well...

We used pvc, but attached the top half of a soda bottle to the end. Cut the top off a 2 ltr soda bottle, so you have the cap end, and a couple inches below that. Cut the cap hole so it's almost as large as the pvc tube. Attach pvc to that (I forget exactly how we attached it, I'm thinking some sort of tape).

You can then rest the flat, cut side of the bottle on the bottom of the tank, and pour the sand through the tube.

You're going to have a sand storm inevitably, but this does help some.