Don't know if this helps, but I found
this blender refill recipe on an SU demo's blog!
I can tell you that rubbing alcohol, or Isopropyl Alcohol will work as a substitute for Ranger Blending solution.
Do you have a bottle of the SU? Does it tell you on the side what the ingredient is?
The Ranger one does list it's ingredients on the side- Isopropyl, Ethanol & Propylene Glycol Methyl Ether!
But I find the Isopropyl Alcohol on it's own works fine. However, I've made a note of this recipe and will give it a try.
In case anyone wants to try it, you can usually find small bottles of glycerine in the baking aisle, it's used to help keep Royal icing soft.