If you ever wondered why your shad wont stay alive and keep getting red nosed then you arent using salt. I went to tractor supply and bought a 50 lb bag of pure rock salt for $5 and put a cup in my homemade bait tank prior to putting in a dozen large shad (4"-8"), I didnt use anything other than salt and the difference was remarkable. After 4 hours of fishing in the hot weather, the shad were so frisky I could barely catch them in the dip net and they were flippin all over the boat while I was trying to hook them, let me tell you this has never happened before with just regular tank treatments of bait medic and it only cost me pennies!! I was using the dip net to get the ammonia bubbles off the surface of the tank water and they still werent getting red nosed, with the other stuff they would be red nosed and lethargic in 2 hrs tops.
Does this mean that all your bait tank will need is salt...probably not but I would definately use it as the base for establishing a healthy bait tank environment. Just my $.02
Good luck fishing