Yeah I thought of that but the only problem would be if it is the same container/batch of salt. Here is a thread using our kit and the person found out he had a bad batch of salt. He also did a test with RO water that seems logical. Let me know what you find out.<a href=showthread.php?s=&postid=8639038#post8639038 target=_blank>Originally posted</a> by Mr. Ugly
If you have a Ca test standard, you can run both kits against that. I use SeaChem for Ca. Comes with a standard of known ppm. You could make up a fresh batch of saltwater and check against that to get a ballpark comparision.