I have the following Data Validation in a cell using the "Custom" validation

=J10<""

This only allows input if there is a value in J10. How would I also include
within this validation a requirement for the user to enter only values
(which may include decimal places)? The problem I am encountering at the
moment is that some users are hitting the space bar to change/remove figures
and this is causing problems within a separate export sheet I have, as it
interprets the values entered as "Space" although visually it looks blank

Thanks