You may want to do more research and read up on some of the threads here. Familiarize yourself with the trials of owning a reef tank.
From you, I get a vibe that you are looking to set it and forget it. That isn't how reef tanks work; they aren't flat panel TVs that you pull out of a box, plug in and enjoy.
Think of your reef tank as a garden. A garden isn't beautiful as soon as you plant. A garden needs to be nurtured, so that it can grow into the beautiful display of colors and aromatic blends that we enjoy.
As
@exnisstech said "Horse before the cart" (But I think he meant cart before the horse).
I wouldn't worry about dosing and automation out of the gate. In a 40 gallon tank, faithful, weekly 20% water changes will replenish elements consumed by your tank. That's all you need to do. But as your tank matures, and demands increase, THEN dosing and automation may be necessary.