The use of Ozone (sometimes called O3) in reef keeping fell out of favour for many years due to the possibly dangerous side effects in terms of stock but has recently been discussed by many hobbyists once more with some making a return to the once popular treatment. As we have some rather more sophisticated understanding of Ozone and its side effects as well as its benefits, more interest has been shown lately with people trying it out once more.

The concerns which are generally raised regarding the use of Ozone are not to be underestimated as the misuse of it can be extremely damaging not only to your stock but also your family. The question remains…does Ozone have a valid place in reef keeping today? There’s no simple answer but the consensus seems to lean towards “yes” as long as those planning to use it do their research thoroughly and fully understand the dangers.
What does Ozone actually do?
The main effect of Ozone in a reef aquarium are can certainly be considered to be that of increased water clarity…even if the water appeared to be very clear before it’s introduction; it’s this which attracts most hobbyists to it’s usage…but what other effects can it have?
• Decreased yellow tinge
• Increased penetration of light
• Decreased algae
• Increased production of skimmate
• Reduced nitrate
• Reduced toxins
• Decreased pathogenic bacteria
That’s a pretty attractive list which is why people are keen to give Ozone a try but as mentioned already, there are issues which can arise from the use of Ozone and which due to their sometimes severe effects, cannot be ignored. What are the negative effects of Ozone? Some of the problems reported by those who have used Ozone include the bleaching of corals and the slowing of invertebrate reproduction…but it’s important to point out that the bleaching effect could in fact be due to the clearer water and increased light penetration. The problems related to invertebrate production have yet to be completely proven to be due to the effects of Ozone.
Despite the fact that today’s filtration systems are now extremely advanced, there will always be a certain amount of fine organic waste particles which may not even be visible to the naked eye but which in a mature reef aquarium can go a long way to spoiling the water quality and clarity, used correctly Ozone can combat this swiftly and thoroughly.
Using Ozone safely
Ozone isn’t without its dangers so great care must be used when utilizing it and there is also some specialist equipment involved, notably an Ozone chamber which is used in conjunction with an air pump, an air dryer and a mixing or contact chamber. Once the air from the pump has been freed of moisture in the dryer, it passes through into the Ozone generator and then, Ozone laden into the mixing chamber where the gas is mixed with aquarium water. Some hobbyists have been known to use skimmers for this purpose but great care should be taken to use only a purpose-made Ozone reactor as Ozone can rot certain materials including rubber.
After passing through the contact chamber, the water should go through activated carbon which will remove some of the oxidants which will result from the process.
Ozone may be either applied in daily batch treatments or continuously; your needs will be dependant on a number of factors including the size of your set-up and the ratio of dissolved organic matter within the water; monitoring of Ozone content should also be well managed and this is best done by measuring the oxygen reduction potential (ORP) via a metre or probes.
Ozonized air should never be allowed to leak into the room in which your aquarium is housed; a carbon filter will go some way towards protecting against leaks in the area of the skimmer or ozone reactor but the air should be monitored closely nonetheless. As with all new procedures concerning your aquarium, keep a very close eye on any changes which occur and be certain that your set-up is safe and correctly installed.
You have just read another great aquarium blog post by iQuatics. If you would like us to blog about a specific subject or if you have your own aquarium blog content which you would like published on our website, please get in touch. Together we can help grow the iQuatics aquarium blog into a vast resource full of combined industry knowledge.