The spacing of the grid lines in Logger Pro are automatically determined based on the axes limits in the graph. You can adjust the axes limits to change the spacing, but there is no way to specify that a tick mark display every x units.

You can adjust the graph options by double-clicking anywhere in the graph and adjusting the color, style, and visibility for both major and minor ticks.

By default, minor ticks do not have lines. If you enable lines for minor ticks, you will get more dense lines.

You can also remove all lines if you set the line style for both ticks to be “No Line.” Removing all lines is often desirable for printing or publication.

In the axes options tab, you can also make all values major ticks.