I would call Rich. If it is a bad, he will have you send it back for it to be swapped out. While it is in transit, you will have to use your hydrofarm to get you by.
If you want to use the Hydrofarm as a backup, then you would place the Hydrofarm's probe similar to your VE100 probe. Then plug your VE100 into the Hydrofarm (Hydrofarm plugged into the wall). Fiddle with the Hydrofarm until it is a few degrees higher than the VE100. If the VE100 gets too hot, the Hydrofarm will shut it off.