adding an additonal disk

So I currently have a script that has the followning variables

$HDD1 = "20" 
$HDD2 = "0"

here is a snipit of the code from my script.  $HDD1 and $HDD2 are in addition to the vmdks based off the template I am using.  There may be a time when I need one additional disk, another time I may need two additional disks.

If I do not need $HDD2, I would prefer to set it to zero as a way of  defining it is not in use.

Right now if I run my script and put $HDD2 = 0 as above.  The script  completes sucessful and only adds  $HDD1 as I would hope, but in powercli it does  display errors pertaining to "invalid value passed for SizeGB" it does not like "0" for $HDD2

I am wondering if I should just add this to the the line below pertianing to $HDD2?   -ErrorAction SilentlyContinue

Or is there a better way to deal with this?

thank you!!!

$vm | Set-VM -NumCpu ( $cpu ) -Confirm:$false
           $vm | New-HardDisk -CapacityGB $HDD1
          $vm | New-HardDisk -CapacityGB $HDD2
          $vm | Set-VM -Notes $Note  -Confirm:$false
                  Start-VM -VM $vmname