Formatting hovertemplate text to show elapsed time correctly

Hi all, I’m trying to format a hovertemplate with some custom data to show elapsed time on my data. I have a dataframe column with elapsed seconds (example of one set goes from 1-5400 seconds), and was hoping to get that displayed as H:M:S format. I tried doing %{customdata|%H:%M:%S}, but that returns Nan, so clearly I’m missing a step in conversion (I don’t think that formatting is meant for elapsed time). Would welcome any advice to format!