Make the bottom drain cover any way that you want, and fasten an airstone on
top. You can drill through the drain cover and have your air line run
through the bottom drain plumbing to the airstone on top, though I have
heard of debris getting caught and slowing or clogging the bottom drain.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Megan" wrote in message
...
He shows how to make a bottom drain, but not one with a diffuser....
"Axolotl" wrote in message
. 130...
"Megan" wrote in
:

take a look at http://www.geocities.com/bickal2000/pond.htm