Sorry,
I didn't mean to imply you should get that copper kit. I got it, because as a monitor, I like to know what these kits are and how they work, if they aren't exhorbitantly expensive.

Another reason to test for copper is if you've been using HTH "double-acting" pucks--they are Tri-chlor and they have "an extra algaecide"---which is copper. It's why I don't like HTH. They are putting in a chemical as a selling point that you don't need, and can cause far more trouble than it's worth, just as a selling point.

Generally, most people don't need a copper or salt test kit, unless they have a heater with a copper core, or an SWG.