This blog is not intended to be a deep dive into the use of ozone (O3) in a reef tank.
We are working on that for 2026.
Ever smelled something sweet, almost metallic, like during a thunderstorm - that’s ozone you’re smelling. For some, it can be picked up right away, while others can’t smell it at all. The same applies when using ozone on a reef tank. Although it's not the same type of ozone (that is, atmospheric ozone), some people are more sensitive to it than others.
You probably already know activated carbon is excellent at removing impurities and dissolved organics from water, but did you know it is also effective at neutralizing ozone (O3) and returning it to oxygen (O2) in water and air? This is one of the reasons why we use bituminous activated carbon in our post-carbon chamber.
Yet from time to time, we would receive an email from a customer with a Mutiny, stating that no matter how often they replaced the carbon in their post-carbon filter, they could still detect a faint trace of ozone in the effluent (exhaust) tube. They asked whether there was anything we could do or make to eliminate the faint ozone smell they detected.
Although we did not have a product for them at the time, this genuine question led us down several rabbit holes. We uncovered the influence of Henry’s Law. Let us geek out for a moment. According to Henry’s Law, the solubility of a gas in water increases proportionally with its partial pressure in the gas phase. This means that increasing the pressure of the ozone gas above the liquid increases the driving force for ozone mass transfer. Higher pressure reduces the rise velocity of gas bubbles, thereby increasing residence time in contact chambers. Source: Sander (2015); Langlais et al. (1991).
I bet you’re asking yourself, what does this all mean? This means the pressure and temperature inside the Mutiny Ozone Reactor chambers are slightly higher than those outside, causing any trace amounts of ozone gas that passed through the activated carbon to expand when it encounters ambient air at standard atmospheric pressure. This can occur more frequently if activated carbon pores become clogged with dissolved organics, or among individuals who are more sensitive to ozone odor.
Armed with this knowledge, we set out to better understand how other industries overcome this challenge. We found that many industrial ozone systems (such as the ones municipal water supplies or bottled beverage plants use) incorporate a series of ambient (air) and aqueous (water) post-filtration scrubbers to ensure all the ozone-treated water falls within the legal OSHA guidelines which state ozone levels in the workplace (they don’t reference on a reef tank) should never exceed an average of 0.10 ppm (parts per million) for 8 hours per day exposure. For more information, see the OSHA website HERE.
We also found that no purpose-built ozone air and water scrubbers are available for reef tanks, so we set out to change that. Our goal was to be the first to design and develop an ozone air and water scrubber for those sensitive to ozone or seeking extra safety and redundancy.
The Birth of the Ozone Air Scrubber & Silencer
After several rounds of R&D and beta testing, we launched the Avast Labs Ozone Air Scrubber & Water Silencer for the Mutiny 2.1. Designed with the same problem-solving focus and community-driven development that define Avast Marine and other Avast Labs products, the Air Scrubber & Water Silencer provides an extra safety barrier for those looking to either fine-tune their Mutiny’s performance or who are extra sensitive to ozone.
What Does a Multi-Stage Approach to Ozone Safety Look Like?
Safe ozone application is a multi-stage process. The Mutiny Reactor and the Air Scrubber work in tandem to eliminate ozone in both its dissolved (Aqueous) and gaseous (Ambient) forms, achieving complete neutralization.
Stage 1: Primary Aqueous Neutralization (Post-Carbon Chamber)
The Mutiny Reactor injects ozone into water, then routes that water through a bituminous carbon chamber. This rapidly converts the vast majority of dissolved ozone back to (O2).
Stage 2: Degassing/Pressure Equalization (Mixing Chamber/Silencer)
The effluent is then routed over bio-balls in a partially submerged chamber (the Scrubber body is installed in 4"–12" of sump water). This crucial 'degassing' stage equalizes pressure, causing any final remaining dissolved ozone to fizz out of the water and escape into the air. The safe, degassed water then returns to the tank.
Stage 3: Final Ambient Neutralization (Air Scrubber)
The ozone-laden air from the degassing chamber travels up the path of least resistance. It is routed directly into the Air Scrubber's dry bituminous carbon bed, where it is safely converted into harmless oxygen before exiting. The Scrubber is the only component specifically designed to capture and safely neutralize this final ambient exhaust.
When to Consider the Ozone Air Scrubber & Silencer?
Pairing the reactor with the Ozone Air Scrubber significantly enhances your system's safety and sensory experience. The following chart outlines some of these use cases:
|
Benefit |
Reason WHY |
|
Safety-First Ecosystem |
The Scrubber completes the process by handling atmospheric ozone intentionally released during the degassing stage, protecting you, your family, and your pets from trace amounts. |
|
Cleaner, Controlled Venting |
Without the Scrubber, the post-carbon effluent line becomes the route for residual ozone. With the Scrubber, this becomes a controlled processing path that reduces emissions to below detectable limits. |
|
Compliance & Redundancy |
Experienced reefkeepers emphasize redundancy. The reactor handles aqueous ozone; the scrubber handles atmospheric ozone. Together, they form a complete, redundant safety solution. |
|
Reduced Noise Profile |
By stabilizing air/water flow, the integrated silencer provides a dedicated acoustic-dampening stage that reduces turbulence-generated noise, which is essential for tanks located in living areas or offices. |
Why Bituminous Activated Carbon Matters
Not all carbon is engineered equally. The Air Scrubber uses bituminous activated carbon, which isn't just better; it’s safer and more efficient. The efficiency of catalytic O3 breakdown depends heavily on pore-size distribution. Bituminous coal-derived carbon offers an appropriate balance of micro- and mesoporosity, delivering a large reactive surface area for rapid, thorough ozone neutralization and durability under prolonged exposure to oxidizing gases. For those with an Ozone Air Scrubber and Silencer already installed, we recommend replacing the carbon every 4–8 weeks if it gets wet, or up to 6-9 months if it stays dry, or immediately if a faint ozone smell is detected. This indicates the carbon is nearly exhausted. For those who want to take the guesswork out of bituminous-activated carbon refills, we offer subscriptions or one-time purchases on our site to help maintain peak performance.
A Solution Tailored to Your Environment
A common question we get is: "If this is so important, why isn't it standard with the Mutiny?"
Every reef setup is different, and we believe in giving our customers the flexibility to choose the level of filtration their environment requires, ensuring you only pay for what you need.
- When optional: If your reactor is located in a garage, in a dedicated fish room with high-volume ventilation, or you only run ozone on a limited schedule (such as at night), the standard Mutiny setup is often sufficient.
- When worth considering: If your reef tank is in a central living space, a small office, or a bedroom, it delivers the "Gold Standard" peace of mind, ensuring a silent, smell-free experience.
Final Thoughts: Ozone, Scrubbers, & Subscriptions
The Ozone Air Scrubber and Silencer exemplifies Avast Labs’ dedication to addressing real-world challenges through thoughtful design. It completes the ozone safety cycle, allowing reefkeepers to benefit from ozone’s performance advantages without sacrificing indoor air quality and silence.
PSA. Order your Avast Labs Ozone Air Scrubber and Water Silencer today, and don't forget to stock up on our Bituminous Activated Carbon Refills to maintain peak safety performance.
