I built my Mixing station in my garage next to RO/DI unit, consisting of 2- 55 gal,(Salt and Ro water) barrels. A work still in process. I have one central pump that pumps water from each barrel as needed via 1/2" pvc pipe up into my attic, across the rafters , inside the wall of my AC closet and feeds 2 separate Acrylic containers behind my sump, one saltwater for Auto water change and the other for ATO. I couldn't pipe directly to sump with float valve as here in S. Florida the temp. in garage reaches 90+ deg. So I fill the 5 gal. ATO reservoir and the 10 gal.saltwater reservoir where it can reach room temp. around 75 deg. My question is 2 part; Knowing that heated salt water losses oxygen I was told I should install an air stone to help with the oxygen drop. Should the stone be in 55 gal. salt barrel or in holding reservoir? Second question: What other issues can I expect, if any, in storing salt/fresh water in containers with various temp?