At my wholesale bait dealer he often gives me a free scoop of the blue stuff (Bait mate) keeps the chlorine down when you need to change or add water
I do several things when I have an expensive amount of bait in holding
I will usually drag a few buckets of river or lake water home, I don't feed them as it only causes extra waste
I also have spare 148 Qt coolers that I keep my Kings in, I will fill these up as the chlorine content tends to dissipate as it sits. I use that for replacement of water, take out 5 and add 5 gallons a day
When I did this many years ago at my old home I used the same cheap bubbler etc, but I tapped a spicket into my plumbing over the top of a 75 gal. bait tank that I let drip into the tank at a very slow rate. Also a drain at the top of the tank, I never needed to do anything and I kept Buckeyes, Bluenose and Toughies (Fat Heads) alive for weeks or even a month
With the first mentioned method I had about 15 lbs. left from my fall season 2010' after my last day on open water (Nov. 30th) they kept until Christmas until they started dying.
Watch out for bait laws, I do not net any of my own minnows anymore, I buy from my local wholesaler/supplier
Tom