With a calcium reactor, your precious reef tank will receive the proper all-around calcium circulation that it deserves. Alongside calcium, you can also trace the magnesium levels to predetermine the alkalinity situation before further steps. However, they're slightly expensive so they might not be the most cost-effective option for beginners. Especially if you're managing a small-scale reef tank, then you don't have to invest in a calcium reactor right away. But once you switch to a larger tank, it's recommended to reconsider this decision. Because calcium reactors will significantly decrease your workload by helping you determine the right Ca²+  dosage levels in a matter of minutes.