My neighbor had a hot water recirculating pump with Built-In Timer. He bought a natural gas hot water tankless heater that had a built in one. So he is going to give me his old pump. I think it will work out perfectly for this system and it can run 24 x 7 if I needed that. So I should have no issue running 4-6 hours a day.
I have one just like this one that I have setup on an intelligent system. It only runs when you turn on a bathroom light or kitchen sink light and then only runs for a set amount of time depending on how far you are from the tank. It works very well.