Looks like you have a good system. I do believe that keeping them cool is also important. Just don't use any water that has been treated with chemical (chlorine) I believe that you will find that minnows do not require food for an extended time. I have maintained minnows for several weeks during cold weather without adding any food to the tank. I believe that keeping the water cold is more important than the aerator although both are important.
:D Bought too cheap and kept too long!!!!:D
:D WALLY:D