I was using an AIO that was handling about 90% of my sulfur smell. I added a small shot of peroxide before the air injection to clean up the other 10%. I wonder if my water has changed, really dry summer but I had to turn my peroxide pump up from 3.5 to 5.5. Then run between the mixer and AIO is very short so I was thinking about putting a retention tank in between to add a little contact time during high use times. Or, I know this is not traditional, but put the AIO after the softener and double duty the softener as a softener/retention tank and putting AIO after softener?