Hanna Checker Calcium HI758

The Hanna Calcium checker is easy to use, fast and extremely accurate. It's faster than most off-the-shelf tests and reports a higher range (the Salifert test maxed out at 500ppm Calcium where the actual levels in my tanks were 545 and 542ppm, respectively - and the Hanna goes up to 600). Unlike the off-the-shelf kits, the Hanna Calcium checker isn't subjective in trying to determine when a color change occurs - so it's far more accurate. Yes, the digital checkers do cost a bit more and you get fewer tests (25) - but you also don't screw up anywhere near the same number of tests, you don't have to test anywhere near as frequently and you're getting way more accurate results (second only to commercial water testing) to help you make important dosing or supplement decisions.