Here's an idea for a useful little project:
1. Buy two 1-1/2" unions that are compatible with the threads on your salt cell.
2. Buy a stick of 1-1/2" PVC (you'll use less than 2 feet of it)
3. Buy two 1-1/2" PVC caps.
There have been several times when I've wished that I've had an insert to take the place of my salt cell while my salt cell is removed for cleaning or service.
Cut the 1-1/2" PVC to the proper length so that it fits together with the male side of the unions to make an insert that is exactly the same length as your salt cell. Glue it all together. My T-15 cell is about 12-3/8" long.
Now when you have the salt cell removed from the system, you can thread the pipe insert in its place. You can still run the pump and filter, vacuum, etc., while you're servicing the salt cell. The salt cell can sit off to the side and fizz happily away while you're backwashing, vacuuming, or doing whatever you need to do.
Some of you might have the salt cell isolated by valves, so you can just close the valves and keep the system operational. I don't have that setup, so when my salt cell is removed, I can't run the system. I could reconfigure the plumbing and incorporate some valves, but this simple solution to make a replacement insert is cheaper and easier.
Finally, cut two pieces of the 1-1/2" PVC pipe to a length of about 3" each. Glue an end cap onto each one, and glue the other end into the female side of the unions. Now you have end caps that you can screw onto the ends of your salt cell, so that you can pour acid into it for cleaning.
When you're done servicing the cell, screw the end caps onto the ends of your pipe insert and store the whole apparatus together. Very convenient!
Have fun!
Juan