Data Validation would like to highlight background when invalid data is present

Hi I have a spreadsheet with a few thousand rows and one of the coloums nees a max character count of 35 I would like to apply the validation but also highlight the background with a colour to show me the affending cells. I would think this would be quite possible but have no idea how as I am quite new and still learning everything i can Have included a spreadsheet with the coloum I need to validate.

Thanks