Don't drop'em! :wink:
You are on the right track looking for a belt like tool for the job.
If you have a stand alone salt tank you can tip the tank toward yourself and gently slide the first one in, holes on the sides.
Now you can stack the blocks for a total of 4.
I advise my clients not to check the tank monthly and add another block as soon as it will fit.
This lets you put one block on top of 3. No bending over or risk of dropping it into a pool of salt water.
If you drop the salt block you risk cracking the container. If this happens you must replace the container.
HTH ~