This solution applies to the 60 Series, 672/675, 350/355, 350/355IS, 370/375, 450, 550/570/574, 650, 515/525.
* Enter setup mode.
* Change P118 from 100% to 0.01%.
* Save Setup and Exit back to weigh mode.
The tank weight should come back. Once the scale is back to weighing properly, change parameter 118 back to a reasonable setting. This parameter change will also prevent the tank from being zeroed off again.
At factory default, P118 is set to 100%. The zero range selects the amount of weight as a percentage of the full scale capacity that can be zeroed out using the [ZERO] key. If the user should not be able to zero the scale 100%, this parameter should be changed.