Question

Is there a way to hide or show a blank cell in a Pivot table for cells that compute to zero?

Answer 1

Use a number format to hide zero values in selected cells:

Follow this procedure to hide zero values in selected cells. If the value in one of these cells changes to a nonzero value, the format of the value will be similar to the general number format.

1.Select the cells that contain the zero (0) values that you want to hide.
2.On the Format menu, click Cells, and then click the Number tab.
3.In the Category list, click Custom.
4.In the Type box, type 0;-0;;@

Notes

- The hidden values appear only in the formula bar — or in the cell if you edit 
    within the cell — and are not printed.
- To display hidden values again, select the cells, click the Cells command on 
    the Format menu, and then click the Number tab. In the Category list, 
    click General to apply the default number format. To redisplay a date or 
    a time, select the appropriate date or time format on the Number tab.

http://office.microsoft.com/en-us/excel-help/display-or-hide-zero-values-HP005199879.aspx