Top up reservoir to main system

For those of you that run a secondary reservoir to maintain constant solution levels within your RDWC systems- do you run a circulating pump or an air stone in the top up res or can it remain stagnant?
normally I have no need for a top up tank but for the occasional trip out of town it would be nice for the peace of mind to have one. I won’t normally be running it but with the occasional trip it would be nice to not have to ask someone to come in and replenish the system.
I’m not talking extended trips either; more like 4 to 5 days. Anything more and I would get someone to assist

I run DWC not RDWC but food for thought…

The goal of bubbling air is to increase dissolved oxygen. If I were running DWC, I'd run air through the secondary res so as to ensure that the water coming in was well oxygenated. I don't mind the extra expense and it would ensure that water is well oxygenated prior to hitting the primary chamber.

Also, unless your system is chilled, you're dealing with slightly reduced DO vs a chilled system.

I run an airstone, but mine is not true RDWC. It’s DWC with a submersible pump in my Rez that runs 15 mins every hour to circulate the the entire system. The extra oxygen can’t hurt.