I actually did this about a week ago. I had the aerator off for a month, then with 8 inches of ice I drilled a few holes on top of the diffuser and turned it on. Wow there was a rank smell coming up thru the holes.

Originally Posted By: Bill Cody
A small hole above the diffuser would allow the bad gasses to escape rather than be spread out under the ice. During really severe winters and/or clogged diffusers expect periodic winterkills with 'weak' amounts of aeration. Always monitor the ice thickness as you approach the diffuser location.