Injecting ozone into aquarium water is nothing new, hobbyists and professionals alike have been using ozone to help improve water clarity, sterilize, and reduce the prevalence of pests for many years. Even with this long-standing history of being very effective, there is still a certain level of hesitation and misunderstanding around the use of ozone in home aquariums. 

Ryan has recently deployed ozone on his own tank here at BRS headquarters and, in partnership with Elliot Lim from Marine Collectors, has put together a list of the top 10 tips you need to know about using ozone. 

1. Ozone is effective

Ozone is a volatile oxidant and when injected into your aquarium water it will quickly oxidize dissolved organic solids and the organic material of bacteria, parasites, and viruses. This will result in a reduction of organics that stain the water yellow and reduce the presence of various pests and pathogens.

2. Management vs. Treatment

The ongoing use of ozone to manage water clarity and reduce pests would be considered "management" and only requires very minimal ozone to be injected on a daily basis. As a treatment, the use of ozone would, hypothetically, only be temporary to address a particular problem such as getting rid of diatoms or dinoflagellates. In this case, the amount of ozone you need isn't well-defined. You also can't be sure the problem is 100% eliminated and won't return thereafter. Not to mention the slow build-up of organics over time will continue to stain the water after the use of ozone is discontinued.

For all intents and purposes, the management approach is what most home aquarists will benefit from because it's safer and generally produces the results we desire - clear water all the time and the reduction of pests! Overdosing with ozone can be deadly to your tank and pose a certain risk to your health if excess ozone is released into the air where it can be breathed in. Using ozone as a treatment is not a well-defined science as it pertains to aquariums and would be considered an "experimental" approach.  

3. A little goes a long way

Nothing good happens fast with a reef tank and more is almost NEVER better. When using ozone, we are finding that very small amounts of ozone for only a short time each day is all you need for ongoing management in your tank. This will result in a slow increase to your ORP which is much safer and still produces the results most hobbyists are looking for.  As you achieve higher, more desirable, ORP levels you can taper off the amount of ozone used each day. 

While the use of ORP to monitor ozone injection is recommended, it is best to control ozone injection using a timer. For example, set the ozonizer to a low output setting and only run it for 1-2 hours daily. Running ozone at night means any residual ozone gas that might escape the tank will likely dissipate before anyone is awake to breathe it in. ORP probes can be fickle and relying on the ORP level to control the rate of ozone injection can quickly lead to overdoses. 

4. Accurate ORP Probes

ORP stands for oxidation-reduction potential and, as described by Ryan, can be understood as the ratio of organics to oxidants. Since ozone is an oxidant, adding ozone to the water increases the ORP levels and we can use this ORP reading to gauge how ozone is affecting our aquarium. It is generally agreed that ORP should measure in the 300-450 mv range when using ozone.

An accurate ORP probe is crucial for using ozone responsibly. While you should use a timer to actually control the ozone injection itself, you need that reliable ORP reading to understand how the ozone is affecting your tank. ORP probes will likely require replacement annually and are generally not the best candidates for re-calibration. Use the ORP solution as a reference to verify the accuracy of your ORP probe on a regular basis. 

5. Ozone is best used on a skimmer with an independent feed pump

Ozone is a gas that is generally injected into the water using a protein skimmer. There are many reports from home aquarists about the use of ozone causing their protein skimmers to collapse; the foam no longer rises to remove organic waste when ozone gas is being injected.  

The theory behind why this happens is based on the design of venturi-driven needle wheel protein skimmers - the most widely used protein skimmers in home aquariums. Using a separate dedicated protein skimmer for the ozone or upgrading to an external recirculating protein skimmer that has a separate feed pump will prove to produce better results. Some protein skimmers are even built with integrated ozone injection ports.

Also, be mindful of the ozone gas escaping your protein skimmer which can be removed with the use of activated carbon. Venting the skimmer cup outside is also an option but running the ozone in the middle of the night really negates any of risk of breathing in the small amounts of ozone that might escape.

6. Ozone may help clear up bacterial infections... among other things

There is no denying that ozone and the resulting increase in oxidants can help to resolve a variety of ailments in an aquarium. We know for certain it will quickly clear up yellow water. Ryan and Elliot have first-hand accounts of ozone clearing up dinos, diatom, and bacterial infections in fish. Commercial wholesale facilities use ozone to effectively sterilize their systems to reduce parasites and viruses which is a well-documented and widely used practice.

That being said, the use of ozone is still in the "trailblazing" phase.. to an extent. Many of these benefits we witness in aquariums are purely anecdotal and not necessarily backed by peer-reviewed research. Yes, we have devised a relatively safe and effective way to use ozone but there is still more to be learned.  Can ozone cure an outbreak of marine ich?  Is ozone an acceptable alternative to quarantine?  How does ozone affect the cycle process and ugly stage? Can you use ozone to kill off certain types of algae?  Answers to these questions and more have yet to be discovered. 

7. Ozone has shown positive effects on curing lymphocytes and other viruses

Elliot shared a first-hand account of ozone being the most plausible solution to a virus in one of his holding tanks. This is not the only account of ozone helping to clear up viral infections and it's exciting to think we have so much more to learn about ozone and how effective it can be.   

8. A new definition of crystal clear

The level of clarity you can achieve with ozone is difficult to achieve without. Most hobbyists are blown away at the difference in clarity that can be seen almost overnight.  

9. More cost-effective than carbon

While it may take a year or two to see the return on your initial investment, the use of ozone instead of carbon is much more cost-effective in the long run. Not the mention it's automated, doesn't require regular maintenance, and is more effective. 

10. Consider the similarity to hydrogen peroxide

Chemically, hydrogen peroxide is water with an extra oxygen molecule while ozone is three oxygen molecules. In both cases, that extra oxygen molecule is the oxidant that attaches to and oxidizes other molecules in the aquarium. This is precisely why we see such similarities in the potential benefits of ozone and peroxide. Peroxide has been used by hobbyists to kill various types of algae, get rid of dinos, and even as an experimental coral dip. The potential power of using oxidants in our aquariums is exciting and we are only just beginning to understand how to harness it.