The Salty Side: Saltwater Aquariums for Beginners


Saltwater Aquarium Nutrients

Nutrients are by far the single most common reason that new hobbyists give up.

Failure to plan for and have measures in place to deal with nutrient control will result in a tank that is ill equipped to cope with the levels that a saltwater aquarium environment can produce.

What are nutrients?

The two nutrients that are imperative to control in a saltwater aquarium are nitrates and phosphates.  

Now, there is a lot of confusion when it comes to nutrients and minerals.  Nutrients refer to nitrates and phosphates.  Minerals refer to trace elements.  

Nutrients = Nitrates & Phosphates

Minerals = Trace Elements

Many think of nutrients as minerals because they equate nutrients in humans to nutrients in coral.  They are two different things.  

Nutrients in a reef aquarium can cause algae growth when levels are excessive and a potential for dinoflagellates to make an appearance if levels are too low or non existent.   

Minerals are trace elements.  They feed coral.

Below is a brief description of both.  (To read more in-depth about phosphates or nitrates, click on the corresponding image.)


In a saltwater aquarium, nitrate is formed as a result of the Nitrogen cycle. The Nitrogen cycle is a natural process in which harmful ammonia and nitrite become nitrate.

Nitrate increases as your bioload increases, and is also exacerbated by the addition of uneaten food and poor water movement amongst other things.  What is important for a new hobbyist to realise is that control of nitrate is an ongoing concern and lack of investment in methods of control from the outset will be to your detriment.


Phosphorous is primarily introduced into a saltwater tank through fish food. It can also be added inadvertently by using an incorrect water source.  As reef-keeping becomes more popular, a rise in the occurrence of phosphate introduction into a saltwater tank is through second hand live rock.  (If you’re unsure of what live rock to start off with, read this article.)

If you are keeping coral, a decrease in phosphates has been shown to cause coral bleaching.  

As with nitrate, phosphate cannot be expected to disappear of it’s own accord. It will be your responsibility to ensure you have a means of reduction and ongoing control.

Lack of control of nitrate and phosphate can result in the ideal environment for the proliferation of many types and unwanted algae like cyanobacteria and dinoflagellates, leading to unsightly tanks.  Excessive nutrients can also be detrimental to coral colouration and growth.

Scroll to Top