It's common for a new system to push up old dead water that stinks. Rule of thumb is to do 15 minutes the first day and double the run times every day after that UNLESS you smell the septic, then stop and do that time again the next day, then continue with doubling times (always stopping if you smell the stink). Some folks have had some fish kills with this rule of thumb so be cautious.

Most people say that the pond gets muddy when you start up, but will clear up within a few weeks. Mind has not, in fact, aeration has been in my pond for over a year now and I just added 18" to my diffusers. They now sit 3 feet off the bottom. Keep in mind that I have not determined the true source of my lack of clearer water, but I suspect that I have some sort of clay that likes to suspend and the diffusers may be encouraging it.

Fish on!,
Noel