I don't use one in my reservoir because it makes the pH drift. I do use the airdomes and figure that the water is getting a bit of aeration from that. My purpose for moving over to the AutoPot system from my bubble buckets was to get rid of some of the maintenance with pH being a massive one. I have also not noticed any real detrimental effects on my plants. My Strawberry Nuggets in an AutoPot is actually bigger than a CremeTasmo in a bubble bucket, and generally when running those two strains side by side the CT dwarfs the SN. However, I did notice that if I used algae extract in powder form it would precipitate out of the water and simply coat the bottom of the res so it required a daily stir. Since then I have swapped over to liquid Floralicious Plus and all has been well since I can only get to my girls about every 3 days.
In the future, I may try one 4 pot system with an air stone in a res and one without to see if there is any noticeable difference but for now I am happy with the simplicity of the system.