Dive Deeper: Info & Tips for Aquarium Reactors

Aquarium reactors are one of the most efficient ways to run chemical or biological filtration in a saltwater system. Whether you're trying to manage nutrients, improve water clarity, or maintain consistent calcium and alkalinity levels, a well-matched reactor can streamline the process.

At Top Shelf Aquatics, we carry a wide range of reactor types — from simple media reactors for carbon or GFO to advanced calcium and CO2 reactors for reef tanks with heavy coral loads. These systems are designed to keep your parameters stable while freeing up space in your sump or display, making maintenance easier and more effective in the long run.

Types of Aquarium Reactors and Their Uses

• Media Reactors (GFO & Carbon):
  These are some of the most commonly used reactors in reef tanks. GFO helps reduce phosphate levels, which in turn limits nuisance algae growth. Activated carbon helps remove discoloration, toxins, and odors. Most media reactors are compact, easy to maintain, and ideal for sumps or in-line setups.
• Calcium Reactors:
  Designed for SPS-heavy systems, calcium reactors dissolve calcium carbonate media using CO2 to maintain stable calcium and alkalinity levels. Once dialed in, these reactors offer one of the most consistent and hands-off methods for supplementing a reef tank.
• CO2 Reactors (Planted & pH Stabilization Use):
  While more common in freshwater planted tanks, CO2 reactors can also be useful in marine systems when paired with a calcium reactor. They maximize CO2 absorption and reduce pH swings by diffusing CO2 efficiently into the water.
• Biopellet Reactors:
  Used for nitrate reduction, biopellet reactors promote the growth of anaerobic bacteria that help export excess nutrients. These are helpful in systems dealing with elevated nitrate levels or as part of a larger nutrient management strategy.
• Multi-Purpose Reactors:
  Many hobbyists opt for reactors that can handle a variety of media types. These versatile designs make it easy to swap out between GFO, carbon, or biopellets depending on your tank’s current needs.

Optimizing Aquarium Reactor Performance

• Match Media to Your Goals:
  Don’t just run carbon or GFO by default. Test your phosphate and nitrate levels, and choose media based on your system’s specific needs. Overusing GFO, for instance, can lead to stripped nutrients and stressed corals, while excessive carbon use may reduce trace elements.
• Use a Dedicated Pump with Flow Control:
  Proper flow rate is key to media efficiency. Too much flow can grind media and reduce its lifespan, while too little can lead to channeling and reduced contact time. A controllable DC pump or a reactor with a built-in flow valve helps maintain ideal conditions.
• Replace Media on a Set Schedule:
  Most media has a lifespan — for example, carbon is typically effective for 2–4 weeks, while GFO may last up to 6. Set a reminder or tie replacements to your water change schedule so you don’t forget to swap out exhausted media.
• Avoid Overpacking the Reactor Chamber:
  Always follow the manufacturer’s media recommendations. Overpacking media can restrict flow, cause clumping, or reduce performance. Using media bags inside the chamber can also help with easy cleanup and prevent clogs.
• Monitor Your Parameters After Media Changes:
  Any time you swap or add new media, keep an eye on your nutrient levels. GFO and biopellets in particular can impact phosphate and nitrate quickly — and sudden drops may affect coral health. Make changes gradually when possible.

Expert Tips for Getting the Most Out of Your Aquarium Reactor

• Label and Date Your Media
  Mark the start date on your reactor or a log sheet to keep track of when media was last changed. This helps prevent running expired or depleted media that can reduce effectiveness.
• Use a Dedicated Flow Control Valve
  Install a control valve between your pump and the reactor input. This lets you fine-tune flow rates depending on the media — especially useful for GFO (gentle tumble), carbon (minimal movement), or biopellets (constant churning).
• Avoid Overloading Media
  More isn’t always better. Follow manufacturer guidelines for media quantity based on tank volume. Too much media can restrict flow or cause overdosing effects, particularly with chemical filter media.
• Pre-Rinse All Media
  Always rinse carbon, GFO, and other loose media with RO/DI or tank water before use to remove fines and prevent cloudiness in your display.
• Don’t Mix Media Types
  If you want to run both carbon and GFO, use separate reactors. These media types have different flow requirements — combining them can lead to inefficiency or clumping.
• Use a pH Controller with Calcium Reactors
  To avoid overdosing or low pH issues, pair your calcium reactor with a pH controller and solenoid to regulate CO₂ input. This helps maintain a stable effluent pH and reduces risk to tank stability.

Installation & Maintenance of Aquarium Reactors

Installation Guidelines

• Choose the Right Placement:
  Install your reactor in a sump or cabinet space with easy access for maintenance. For external models, ensure the area stays dry and allows for safe tubing routing.
  
  
• Use the Correct Pump Size:
  Match the pump flow rate to the specific media being used. GFO and carbon generally require lower flow, while biopellets and some calcium reactors need higher flow rates or recirculating setups.
  
  
• Secure Tubing and Fittings:
  Double-check all tubing connections to prevent leaks or disconnections. Use clamps where needed and avoid kinks that might restrict flow.
  
  
• Dial in Effluent Flow (Calcium Reactors):
  Start with a slow drip rate and adjust gradually. Use a graduated cylinder to measure ml/min of effluent and pair with CO₂ bubble count for consistent dosing.
  
  

Maintenance Tips

• Replace Media on Schedule:
  Most media types (carbon, GFO, biopellets) need replacement every 2–6 weeks depending on bio-load and water quality. Calcium reactor media typically lasts several months but should be topped off as it dissolves.
  
  
• Clean the Reactor Body Every 3–6 Months:
  Disassemble the reactor to remove buildup, algae, or clogs. Use a soft brush and vinegar solution if necessary. Rinse thoroughly before reinstalling.
  
  
• Inspect Pump and Tubing:
  Look for signs of wear, salt creep, or flow restriction. Clean pump impellers and replace tubing annually or as needed.
  
  
• Check Flow Consistency:
  Over time, flow can drop due to clogged sponges or fines buildup. Monitor output and clean internal components to maintain stable performance.
  
  
• Monitor Effluent pH (Calcium Reactors):
  Use a reliable pH probe to keep track of your calcium reactor’s output. Maintain recommended levels to avoid over-dissolving media or driving down tank pH.