Corals are expensive. Well, the nice ones are anyway. This is not a cheap hobby. You will have to replace trace elements that are used up by the corals. This can be done with water changes. So, they help in multiple ways. Another way is dosing the elements. this is also expensive.
i would stop trying to figure how to do less work, and start trying to figure how to make the work you are doing easier.
My tank is close to a sink. I use a 10' hose and pump the water out of the tank into the sink, then I reverse the hose and pump, pumping the water from my drum to the tank.
You can put your drum on wheels if that helps.