Over the years I have used both two-part dosing and calcium reactors for calcium and alkalinity supplementation. Two-part is good because it allows for precise dosing of each component. And it provides important major and minor trace elements for corals.

However, two-part can be expensive if you use pricey, ready-made solutions and have corals that require a lot calcium and alkalinity. With this new tank I decided to use a calcium reactor since I was planning to have a lot of SPS.

One drawback with a calcium reactor is that it will lower a tank’s pH. How does a reactor lower pH? Well, carbon dioxide is injected into the reactor to lower pH to help dissolve calcium-based media inside. This calcium-rich liquid or effluent is then dripped back into the tank.

Using Kalkwasser to Elevate pH

Nonetheless, there are some things you can do to elevate the pH coming out of a reactor. One is to use kalkwasser. Hydroxide ions in the kalkwasser use carbon dioxide to increase alkalinity and, as a result, removes excess C02 and increases pH.

Kalkwasser can be added by running RO/DI water via an auto top-off device through a reactor with kalkwasser. Some of these kalk reactors utilize stirrers on the bottom to mix and saturate the kalk. In the past I have used a reactor with a small external pump to mix the kalk.

Due to photosynthesis, the pH in a tank will drop at night when the tank lights are off so it is best to boost the pH during this time with kalk. I typically set my pump to run 4 times during the overnight hours for 15 minutes a pop to stir the kalk.

Another Way to Elevate pH

A second way to elevate pH is to have a second chamber on a calcium reactor to help absorb the excess carbon dioxide. I chose a brand-new model of calcium reactor manufactured by Reef Octopus and distributed by CoralVue. Both chambers on this Reef Octopus VarioS CR3000 reactor are 7 inches wide and nineteen inches tall.

Peninsula Tank Build – Calcium & Alkalinity Supplementation –  MORE