I utilise a number of rows into which I place the steps of a chemical process.

The rows for the chemical steps are between row 20 and 87.

I enter a chemical process which takes a number of these rows to complete. I
then have to manually hide the unused rows as they are not required for
printing and for getting to other rows below row 87.

Is there a macro/code I can use which will check for empty cells in column B
(where the process is entered) in rows 20-87 so that these rows will be
automatically hidden. I already have a macro to unhide these cells.

I would need the code to work in any selected sheet as the chemical process
stages may be entered over 10 different sheets (St1, St2, St3 etc).

can anyone help?