In the ground mount section the option "Visualize ground clearance" can be selected, this will open a new window.
Here you can select the boundaries in which racks have been placed. Either individual boundaries with the "select on drawing" option or all boundaries with "select all".
When those boundaries have been selected you will see multiple values above the colored bar.
On top you see the bottom side height, this is the value you entered when creating your racks. It represents the height of the modules above the ground. But of course the height can not be identical for the whole rack when working with sloped terrain.
So the value left above the bar represents the module that is closest to the ground and the value on the right represents the furthest one from the ground. You can now adjust the sliders to change the colorization and press apply to show these values on the project.
When aplied this now shows you the height of each modules in the bottom row of racks. This way you can locate and prevent any mistakes like collisions with the ground.