Thanks Bill. The pond was finished August 04 and filled in December 04. The water has steadily been clearing since January. Secchi disc readings went from 12 inches in Jan. to 36 inches a few days ago. Due to the ponds age I know it's not muck.

When I've raised the diffusers which are attached to 18"Lx18"W plexiglass squares that came with the unit, I've seen clay on the plexiglass, usually the bottom like it was sitting properly on the bottom.

What suggestions do you have for a set-up other than the plexiglass I already have the diffusers attached to that would keep the diffusers upright as they are lowered?

I kind of think you were right about the diffusers in the deep water bringing up material that hasn't settled all the way to the bottom yet. The discoloration is about 15 feet in diameter around the boils from the diffusers. I got to looking this afternoon and even the 10ft diffuser has a discoloration around it. Secchi disc readings range from about 16-20 inches in the discolored areas and 32 inches in the areas outside of the boils up to 36 inches near shore.

What exactly is 'detritus' and should I stop the aerator if it is bringing it up?

Any further answers would be appreciated. Thanks.