New, but no guarantee?
Some cartridges have square shaped threads and some have sharp angled threads. I wonder if the seller didn't know this and sold you a unit they thought they had repaired. Can you see what kind of threads these are?
I have parts for both, if you want to bring the unit to Murray where we can check it out and make sure the part fits and holds pressure. Alternatively, water softener companies often have the parts. Maybe there is a company near you?
Aloha,
Mark
