Auto top-off holding tank- circulation?

[180large]

I was wondering what the preferred method of circulating holding tanks is.
Powerheads, or an air stone maybe? And is it even necessary ? Thanks

 

[shifty51008]

i have never had any circulation in my top off water, just a lid

 

[todd141]

i have never had any circulation in my top off water, just a lid

Same here.

 

[Reverend Reefer]

me neither, no circulation in my top off water resevoir.