Calcium Reactor

Setting up a calcium reactor can significantly benefit a reef aquarium by maintaining stable calcium, alkalinity, and magnesium levels for coral growth. Here's a step-by-step guide to setting up a calcium reactor:

1. Gather the Necessary Equipment

Before starting, ensure you have the following equipment:

• Calcium Reactor Unit
• CO₂ System (CO₂ tank, regulator, needle valve, solenoid, and bubble counter)
• pH Controller (optional but recommended)
• Feed Pump (to deliver water to the reactor)
• Reactor Media (calcium carbonate-based media)
• pH Probe (for monitoring inside the reactor)
• Tubing for water and CO₂ lines
• Check Valve (to prevent water backflow into the CO₂ system)
• Circulation Pump (usually built into the reactor)

2. Choose a Location for the Reactor

Place the calcium reactor close to the sump or aquarium for easy water access. Ensure there is enough space for the CO₂ tank and to perform maintenance.

3. Install the Reactor Media

• Open the reactor and add the calcium carbonate media.
• Rinse the media briefly with RO/DI water to remove dust particles.
• Fill the reactor chamber about 2/3 to 3/4 full with media.

4. Connect the Feed Pump

The feed pump delivers aquarium water into the calcium reactor. Options include:

• Sump Connection: Use a small pump (like a peristaltic or low-flow pump) to pull water from the sump into the reactor.
• Manifold: If you use a manifold from your return pump, connect it to the reactor for a controlled flow rate.

5. Connect the CO₂ System

• Attach the CO₂ regulator to the CO₂ tank and ensure it is securely fastened.
• Connect the solenoid valve and needle valve to the regulator.
• Connect the tubing to the bubble counter and then to the CO₂ input on the reactor.
• Use a check valve on the CO₂ line to prevent water backflow.

6. Install the pH Probe (if using a pH Controller)

• Place the pH probe in the designated port of the reactor.
• If using a pH controller, calibrate the probe first using pH 7.0 and pH 4.0 calibration fluids.
• Connect the probe to the pH controller to monitor and maintain the reactor's internal pH.

7. Start the Water Flow

• Start the feed pump to allow water to flow into the reactor.
• Adjust the flow rate to a slow drip exiting the reactor effluent line.
  • Recommended starting flow: ~30-50 ml/min (adjust based on tank demand later).

8. Adjust the CO₂ Input

• Open the CO₂ regulator and start with a low bubble rate in the bubble counter (e.g., ~1 bubble per second).
• Monitor the pH inside the reactor. The target pH depends on your reactor media but is typically between 6.5 and 6.8 to dissolve the media.

9. Fine-Tune Reactor Settings

• Monitor alkalinity in the tank and adjust the reactor settings accordingly:
  • If alkalinity is too low: Increase the CO₂ bubble rate (more acidic, faster dissolution).
  • If alkalinity is too high: Decrease the CO₂ bubble rate (less acidic, slower dissolution).
• Check Effluent: The reactor effluent should have a high alkalinity reading (e.g., 20-30 dKH).

10. Ongoing Monitoring and Maintenance

• Test your tank alkalinity, calcium, and magnesium levels regularly to ensure stability.
• Refill the reactor media and CO₂ tank as needed.
• Clean the reactor, pH probe, and tubing during regular maintenance intervals.

Key Notes:

• CO₂ Bubble Rate: Start low and increase gradually to avoid sudden changes in water chemistry.
• Effluent Flow Rate: Adjust for the tank's calcium and alkalinity demands.
• pH Controller: Automates CO₂ control by turning off the solenoid when pH drops too low.
• Safety: Always use a check valve to prevent water from backing into the CO₂ system.

Once the reactor is tuned correctly, it will provide a steady supply of calcium and alkalinity to keep corals thriving. Regular testing is key to maintaining stable parameters.