Conditional format not carrying over from linked cell
 

I have a cell...
Sheet1!D30
that is conditionally formatted to be red if the cell is blank, yellow if
the date is over 90 days, and green if less than 90 days. Works great.

I then linked it to another sheet....
=IF(Sheet1!D30="","",'Sheet1'!D30)
but the formatting didn't transfer and it now stays yellow. I'm guessing
because the cell is not blank anymore. The conditional format is formula
equals
=ISBLANK(D30)=TRUE

Any way to keep the format from the original cell into the new linked cell?