Without math I can't really see how you can set up and maintain a tank!
Especially when planning a new build: flow rates, how much water the overflow will/can handle, pvc dimensions, volumes, dosing calculations, watt/amp requirements... the list goes on and on.
I like math so I use it all the time. Newest one I wanted to know what my actual heat required was on a cold winter morning so I unplugged my heaters and measured the temperature drop in one hour.