Making two seperated tanks whole and showing the liquid percentage...

Hello Everyone,

I finished drawing two (water) tanks and a pipe line between them. However i can not find how to make each of those prism as an object and showing the percentage of liquid within them...

Can anyone help me how to??

Your helps are highly appreciated.

You may find the m file attached. (The dimension datas are entered from a gui as global values, also i want to be able to enter percentage from same gui as well)