The internal height is important information as we need this to ensure you are sent the monitor with the correctly sized cable for your tank.
To measure this, you will need:
Measuring device (measuring stick, clean pipe/stick)
A pen/pencil
Tape measure
Open the top of your tank by the fill pipe and dip in your measuring device until this touches the bottom of your tank. Once this has touched the bottom of your tank, use your pen/pencil to then mark your measuring device where it sticks out of your tank at the neck of the fill pipe.
Take out the measuring device and measure the bottom of this to the pen/pencil mark made. This will be the internal height of your tank.
