Calcium is one of the most essential elements for the growth and health of coral and invertebrates in a reef aquarium. You’ll need to watch for calcium levels to keep your Corals healthy.
Luckily, the steps needed to raise and maintain calcium are well-documented. Thanks to years of experience and proven methodologies, you can easily learn how to maintain a stable reef environment.
Here’s what you need to know for adding and maintaining calcium levels in a reef aquarium.
Test new reef tanks daily and established tanks weekly to check the levels of calcium, alkalinity, and magnesium. A calcium reading of 400 parts per million (ppm) or lower is considered low.
Raise calcium levels using dissolvable calcium supplements, calcium hydroxide, or a water change with a calcium-enriched salt mix. You can also consider installing a calcium reactor device to help maintain calcium levels.
Test the Water of Your Reef Aquarium
Before adding supplements to your reef aquarium, you need to know the current levels of calcium, alkalinity, and magnesium.
Here’s a rundown of the acceptable levels of each element:
- Calcium: 400 to 450 ppm
- Alkalinity: 8 to 12 dKH (143 to 215 ppm)
- Magnesium: 1200 to 1400 ppm
You can use test strips, electronic testers, or testing kits to analyze the content of your tank water. Test strips are the most affordable, but least exact. Electronic testers are reliable but cost more.
Calcium test kits are the most accurate when used correctly. You can test calcium concentrations and adjust the supplementation methods as necessary.
Test New Aquariums Daily
If your tank is still getting established, test it daily. Check the levels of calcium, alkalinity, and magnesium each day until you get a good balance of nutrients.
It can take about six weeks for a reef tank to fully cycle after you first set it up. However, it may take three to six months for it to become well-established. As the tank becomes more established, maintaining calcium levels becomes easier.
Test Established Aquariums Weekly
After achieving a good balance of nutrients in your tank, you need to keep things balanced. This involves continued testing.
However, instead of testing daily, you can eventually start testing once per week. Continue to check the calcium, alkalinity, and magnesium levels of the water and adjust your dosing as needed.
How to Increase Calcium Levels
The calcium levels won’t increase on their own. You need to add calcium in some form. Here are four options for raising and maintaining calcium.
Calcium Reactors
Calcium reactors are devices that you add to your tank to help automate the process of supporting ideal calcium levels. The device has a chamber filled with calcium carbonate media.
Carbon dioxide (CO2) is used to help dissolve the media, which releases calcium into the water. As the calcium levels in the aquarium are depleted, the reactor delivers a calcium-rich solution. Along with a calcium reactor, you’ll need a CO2 delivery system. Depending on the size of your tank, you may spend several hundred dollars on extra equipment. The main advantage is that a calcium reactor offers greater stability compared to manual methods of regulating calcium levels.
Calcium Supplements
Calcium supplements are available in liquid or powder form. The supplements may include calcium chloride, calcium carbonate, or a combination of both. They’re added directly to the tank using the manufacturer’s instructions.
Most calcium supplements include dissolvable tabs that you simply drop in the tank. Liquid calcium supplements often include measuring lines on the cap. The amount of liquid added depends on the size of the tank and the current calcium levels.
Calcium supplements are also frequently used with alkalinity and magnesium supplements as part of a multi-dose approach for maintaining optimal levels of all three elements. This requires you to monitor all three readings and adjust the dosage of each supplement accordingly.
Calcium Hydroxide
Calcium hydroxide, sometimes called kalkwasser, is a solution that helps raise calcium levels and maintain the stability of pH and alkalinity levels.
Kalkwasser is sold in powder form and dissolved in freshwater. Wait for the powder to mostly dissolve and settle on the bottom. The clear liquid on top is gradually added to the reef tank to help stabilize calcium and alkalinity levels.
Calcium-Enriched Salt Mix
Performing regular water changes with a calcium-enriched salt mix is another method for maintaining proper calcium levels. Using a salt mix product with calcium, such as Instant Ocean salt mixes for reef tanks, you can easily replenish the aquarium water’s calcium levels.
Start with a 10% to 20% water change each day while using as much salt mix as the manufacturer recommends for your tank size. You should notice a gradual increase in the calcium levels with each water change.
How to Reduce Calcium Levels
In some situations, you may find that your calcium levels are too high. This typically occurs due to incorrect dosing using one of the previous steps.
Stop Adding Calcium
If you stop adding calcium, levels should gradually decrease in the coming weeks. The corals will naturally consume excess calcium, helping to bring the levels down to an acceptable amount.
Test the calcium levels weekly. After you reach the ideal reading, start adding calcium again, but start with a lower amount compared to your previous efforts.
Complete a Water Change
If you want to bring the calcium levels down quickly, complete a water change without calcium dosing. Performing a water change can lower calcium levels without significantly impacting the levels of alkalinity, magnesium, and other elements.
Under normal circumstances, you should complete a 10% water change each week. This means replacing 10 gallons of water for every 100 gallons of tank size.
If you’ve got too much calcium, change out more of the water. For example, a 25% to 50% water change using a non-calcium-enriched salt mix should help lower calcium levels.
Summary
Maintaining a healthy reef aquarium requires you to maintain ideal levels of calcium, alkalinity, and magnesium. This typically involves dosing the water with supplements. Chemicals are added to help ensure a balance of elements.
Test your water daily during setup and weekly after it’s established. If calcium levels are below 400 ppm, you need to add more. Calcium supplements, calcium hydroxide, and calcium-enriched salt mixes can be used to steadily increase calcium levels. For a more advanced setup, you can consider using a calcium reactor.
FAQ
Why Does My Reef Aquarium Need Calcium?
Calcium is a necessary nutrient for maintaining your reef aquarium. Coral, algae, and other organisms rely on calcium for growth.
Is Too Much Calcium in a Reef Tank Bad?
Overdosing the amount of calcium makes it more difficult to maintain healthy values of alkalinity, magnesium, and other elements. This may gradually kill organisms, including coral.
What Is the Limit to Raise Calcium in a Reef Tank Per Day?
Many aquarists recommend increasing the calcium by no more than 50 to 100 ppm per day. However, if calcium levels are below 100 ppm, a higher dose may be needed to help raise the values quickly.
