On Sun, 4 Sep 2011 07:07:05 -0700 (PDT), wrote:

But my first thought would be to
apply air at the pool pad and see where bubbles
come out. If you have lots of air coming out
the bottom drain and no brown water, I'd say
it's unlikely a clog you're dealing with.

That's a great diagnostic technique ...

I will see what I can rig to go from the air nozzle to the 2 inch opening
at the bottom of the debris cannister first.

A diagram of the layout, roughly, is in this web page:
http://www.starbacks.ca/Eureka/1034/...ntpcc2000.html