You got that right. I have a septic, buddy has an aerobic. Nothing but trouble with diaphragms in the pumps failing, etc.Aerobic systems are from the devil . . . they're great when they work but can be very expensive when stuff breaks. I'd recommend keeping an extra air pump on hand.
First time it failed, he called the ONLY repair guy in this area, came out and said it was going to be a $500 fix.
Buddy got online and watched some video's. $20 bucks later mostly for fast shipping he had a diaphragm to fix what was wrong.