Conditional formatting issue

Hello all -
I am having an issue getting an conditional format to work correctly.

My goal is to have it where if there is nothing in a particular field, that it stays white.
For whatever reason, the blank field as shown in my attachment is coming up red.
All the other fields in column O are working as needed. Just not sure why this is coming up red for cell O24.

When there is a "0" in C24 & D24, O24 turns from red to white and works ok.
Just not sure why if C24, D24 AND 024 are blank, why it would be red. I am sure it is something small....

I have an attachment with screen prints showing my formulas and such.

Any help would be appreciated.

Thanks.
Dave

Martin - perfect.
Thank you.
Dave