I will send you more informations about PID controller.
Please, could you modify system as I write in next two tasks ??
1.is possible modify system to turn off automaticly inflow when liquid levels of tank1 and tank 2 get maximum range ?
2.Please set maximum range both of tanks set to 0,14 and please, reconfigure range of visualization to better see line of h1 . it is too high :)