Tuning your calcium reactor can be a little frustrating, especially if you have never set one up before. In this video, we are going to show you how to dial in your calcium reactor to help get your SPS corals growing as fast as possible and to provide some helpful insight into how a calcium reactor works.

The concept of a calcium reactor is very simple. Basically, you are taking coral skeleton or a calcium-carbonate-based media and using acidic salt water to melt it down, releasing elements that will enrich your aquarium water with the proper levels of calcium and alkalinity.

When using calcium reactor media you are melting down exactly what you are trying to grow-coral skeleton. In addition to calcium and alkalinity, most media also contains strontium and other trace elements. With the use of magnesium media such as the Brightwell Aquatics NeoMag or Zeovit ZeoMag, the reactor can even help maintain your magnesium levels.

The trick to dialing in your reactor is to match the rate of supplementation from the reactor with the rate of consumption by your corals. The more acidic the water inside your reactor, the more media it will melt. The more water you process through the reactor, the more calcium and other elements will be added to the tank.

In order to melt media, you need to maintain a pH of 6.5-6.9 inside the calcium reactor. A pH monitor, such as the American Marine Pinpoint, or a pH controller, such as the one included with some Neptune Systems Apex controllers, will come in very handy to monitor and control the pH. A cheaper alternative is to use a pH test kit but this does require much more effort.

Most of the calcium reactors available today have a built-in pH probe port so you can easily and accurately measure the pH inside the reactor.

If the pH is not maintained properly, the media will either not melt fast enough or quickly turn into mush; this is why it is so important to maintain pH inside the reactor within the recommended range. Be sure you have a solid understanding of CO2 injection and how it affects the pH inside the reactor. Basically, the more CO2 you add, the lower the pH in the reactor will go.

A pH controller, along with an electronic solenoid on your CO2 regulator, is the best way to ensure pH is maintained within the proper range. The controller will read the pH in your reactor and only allow for CO2 injection when pH rises above the desired range. This avoids the hassle of constantly having the adjust the bubble count on your reactor.

Next, you need to look at the effluent (outgoing liquid) drip-rate. One simple way to manage how much water is ‘enriched’ by your calcium reactor is to adjust the effluent drip-rate. If you have a low calcium demand, you will need a slower effluent drip-rate. If you have a high calcium demand, you will need a faster drip-rate.

Now here is the key that ties everything together; changing the effluent drip rate will change the pH inside the calcium reactor.

A faster drip rate means water is spending less time inside the calcium reactor, which means that more CO2 will be needed to maintain the desired 6.5-6.9 pH. Conversely, a slower drip rate means water is spending more time inside the reactor, so less CO2 is needed.

Once your calcium reactor has had a chance to break in for a week or two, you will want to test your calcium and alkalinity levels weekly and make the appropriate adjustments to your calcium reactor.

Make the very small adjustments and allow ample time for changes to take effect inside the reactor and in your tank. Often, it is easier to set the calcium reactor to keep parameters stable.  Then, use liquid additives to occasionally raise the calcium and/or alkalinity levels as needed until your reactor is properly tuned. It will take at least 2-4 weeks to properly dial in your reactor. As your tank grows, coral consumption will increase; you will need to adjust your reactor as well to meet the higher demand.

Effluent water exiting the calcium reactor will have a low pH due to the injection of CO2. Dripping the water into your refugium can be great for helping to avoid a drastic pH drop in your display aquarium. The macroalgae in your refugium will use some of the CO2 dissolved into the water, raise the pH of the water, and help prevent drastic pH drops in your aquarium.

Alternatively, you can use an extra reaction chamber, such as the Aquamaxx Effluent Chamber, which is a canister filled with calcium reactor media that will help increase pH of your effluent water before it is dripped back into your aquarium. Most media reactors can also can be converted fairly easily into an inexpensive effluent chamber.