"RichToyBox" wrote in message
newsaAwa.600983$Zo.131132@sccrnsc03...
BV,

The diffuser makes the water pull along the bottom, rather than coming
straight down to the bottom drain. With a diffuser the area of the pond
cleaned is much larger. I don't use a diffuser and feel that my bottom
drain does an excellent job, but it supposedly would be even better with
diffuser.

I have parts for my own DIY design. I just haven't installed it yet.

BV.