"Bob Nielsen" wrote in message
...
I believe gravel is preferable to sand. If the sand becomes wet
it might block the end of the tube preventing adequate drainage, thus
defeating the purpose.

Bob, N7XY

OH, damn good advice.... how about pea gravel, or maybe 3/8" rock? it would
allow
drainage very well (many french drains and other water drain systems use pea
gravel or
small rock to allow water passage or filtration)....

Clint
KB5ZHT