Hopefully Steve, we can get Bill Cody in on this question. He gave a very interesting presentation at last years Pond Boss convention regarding this subject. If I recall correctly (or IIRC), raking worked better than the bacteria because it suspended the muck and essentially aerated it. But don't take any advice from me, lets get an expert opinion.

"Paging Bill Cody, Commander Cody, please pick up the white courtesy phone located in the main lobby."

JHAP
~~~~~~~~~~
"My mind is a raging torrent, flooded with rivulets of thought cascading into a waterfall of creative alternatives."
...Hedley Lamarr (that's Hedley not Hedy)