Reverse Osmosis in the Reef Aquarium – Do I Need It?

The reef aquarium hobby is a relatively expensive hobby, especially when it comes to purchasing all the required equipment. The tank and stand are generally where it all starts, however, the cost doesn’t end there. The list of equipment we need to get the aquarium ready for inhabitants is seemingly endless. In terms of equipment, we need to make decisions regarding lighting, filtration and flow, just to name a few. Whilst there are some items that we can probably do without, there are those that are absolutely crucial to the life support system we need to create, to support the delicate animals in our reef aquariums. Reverse osmosis DI systems are one of those crucial items.

The invertebrates that we keep in our reef aquariums are simply unable to cope with changes and elevations of certain elements in water chemistry. Even the slightest rise in heavy metal concentration can spell disaster in a reef aquarium. Corals and other invertebrates are simply incapable of surviving in aquariums with high levels of these elements. Add to this the concern of high nutrients being found in some Australian water supplies, as a result of fertilisation runoff in areas that surround our water catchments.

With high levels of nutrients in our tap water and battles with algae in reef aquariums being one of the leading reasons for shutdowns, whether or not you need a reverse osmosis system starts to become very obvious.

The Decline in Australian Tapwater Quality

Australian tap water quality has changed dramatically over the past three decades. In the early 1980s, it would have been acceptable to use tap water to fill an aquarium.  Today, that simply is not the case and it is not a risk most aquarists would even consider taking with their reef aquariums. With growing populations in our cities, the challenge of providing all homes with drinkable water means finding new ways of disinfecting water. It is these disinfectants, the introduction of chloramines, that play a very big role in making tap water unsuitable for aquarium use. Chloramines are a resilient combination of chlorine and ammonia, both individually deadly to all reef aquarium inhabitants.

In the vast majority of Australian towns and cities, the tap water is very drinkable. Our local councils and water supply networks around the country work tirelessly to ensure that the water we draw from our faucets is safe for human consumption. They test and monitor levels of certain elements known to be harmful to human beings but the criteria used here is a benchmark against human tolerance and not that of our reef aquarium inhabitants. The chlorine and chloramine levels safe for human drinking water alone are enough to decimate a reef aquarium.

Delicate Life Forms in Our Reef Aquariums

Since the 1980’s, another major change in the hobby has been the types of animals that we are keeping. We are no longer content with the more forgiving soft corals. Even beginners have their sights set on the beautiful, brightly coloured stony corals. We are keeping delicate crustaceans and invertebrates that simply will not tolerate high levels of heavy metals, nutrients and the myriad of other toxic contaminants found in Australian tap water. Using untreated tap water in any aquarium is simply a dangerous risk with an uncertain outcome.

So this brings us back to the initial question. Do we really need to be using reverse osmosis systems to produce water for our reef aquariums? Absolutely, without a doubt! Without RO/DI water, it is simply not possible to keep a healthy, thriving reef aquarium. The modern-day RO/DI (deionisation) systems of today are capable of removing every element from our tap water, giving the aquarist the opportunity to replace only the elements that our reef aquariums require.