With natural seawater containing around 420ppm, Calcium is both a major ion and a critical building block for a myriad of calcifying organisms in the oceans. These organisms range from colourful reef-building SPS corals, to tiny molluscs, to a whole host of other life-forms. Along with Alkalinity and Magnesium (to which it is intrinsically linked) Calcium should therefore be carefully monitored and controlled in a reef system. If levels fall out of balance the organisms that rely on it are likely to be adversely affected.
There are numerous test kits for Calcium available to hobbyists and most of these rely on a test in which a colour change, evaluated ‘by eye’, indicates a result. Unfortunately, these tests can be rather hard to interpret, even for those who don’t have difficulty distinguishing between subtle shades of colour. Furthermore, natural daylight and a white viewing background can be essential for such tests and, simple as it sounds, these minor barriers can serve to sometimes delay or even rule out testing in our experience.
The Hanna Calcium Checker, like the Phosphate ULR model we reviewed recently, is different in that it analyses the subtle colour change for you. You don’t need to evaluate it yourself, instead the unit gives you an exact reading in ppm. Neatly contained in a sturdy storage box (much better than a cardboard box) we found all the components necessary were present and in good order along with useful instructions. The actual test process isn’t technically simpler than a ‘normal’ Calcium test, but regular repetition should see it become quick to perform (take care not to mix up 0.1ml with 1.0ml as thi is easily done!). Our only minor gripe was that we found the pointed tip of the syringe didn’t appear to work well, but luckily we had one from another kit.
Coming with 25 reagent sachets, this isn’t the cheapest kit (RRP £55) but we’ve certainly found it to be the most convenient to use. Although it isn’t really ‘simpler’ to perform than standard Calcium tests, the definitive result given makes this an extremly useful tool in our opinion, and obviously you don’t need to worry about setting-up (lighting etc) anywhere near as much with this device.