tank.lua

component = require("component")
tank = component.tank_controller

tInfo = tank.getFluidInTank(4)

amount = tInfo[0].amount
capacity = tInfo[0].capacity
label = tInfo[0].label

percent = amount/capacity*100

math.floor(percent + 0.5)

print("Liquid type : "..label)
print("Amount      : "..amount)
print("Tank Cap.   : "..capacity)
print("% Full      : "..percent)