OK, perhaps we should start again from scratch.

Please explain exactly what you mean by "reed relay inputs"

Are the reed relays part of your design, or are they in the external equipment you are monitoring?

If the reed relays are part of your design - on your PCB - then you can use them to provide isolation as I described here, and you do not need opto-isolators.

However, if the reed relays are in the external equipment, then you just treat them as any other external switch contact. The fact that they are reed relays is irrelevant.
An opto isolator would make sense in this case.