Put simply, the biological cycle that happens within your aquarium starts with wasted food & fish waste. This is converted into ammonia, which is then converted in to Nitrite, the that is converted into Nitrate.

Though corals and fish needs some Nitrate to thrive, high numbers will reduce their vibrancy, growth rates & may put their lives in danger.

10-20% Water changes are unlikely to have a significant effect of lowering Nitrates in your fish tank.

Here are the top 5 ways you can reduce your Nitrates within your Aquarium.

5. Reduced Feeding

Overfed Fish
It’s tempting, but just don’t do it!

We all love feeding our fish, but over feeding your tank to the point where food is sent to your filtration, or it is left uneaten at the bottom of your tank will increase the Nitrate within your tank.

Reducing the amount you feed, will reduce the amount of waste, which in turn will reduce the amount of ammonia etc for the denitrification bacteria to consume.

live rock
live rock

4. More Live Rock

Live rock is called live rock because of the bacteria that grows on it.

The more live rock you have, the more bacteria you have, the more bacteria you have, the easier it is for the bacteria to process the waste.

Live rock also offers critters such as copepods, bristleworms, peanut worms and other great additions to your clean up crew, a perfect place to hide. All of these helpful hitch-hikers will help reduce the waste within your aquarium, which will help reduce nitrates.

Live rock substitutes like ceramic media would also have the same effect.

3. Carbon Dosing – The Cheap Way

Carbon dosing doesn’t have to be expensive & you can use a couple of items to do it that can be found in most local supermarkets.

Common Carbon Sources
Common Carbon Sources
  1. Vodka Dosing.
  2. Sugar Dosing.
  3. Vinigar

By adding carbon to your aquarium, you are increase the amount of bacteria within your tank, this allows the bacteria to deal with the nasty bacteria in a more effective manner.

Once your bacteria can keep up with the denitrification required, your skimmer will take over and remove the Nitrate.

You can use the below chart to work out how much to dose. This is based on 80% proof unflavoured vodka in ml. To use this for sugar, 0.1ml of vodka is equal to 1/10th of a teaspoon of sugar.

NOTE: You need an efficient skimmer for this to work properly

2. Grow Algae

Chaeto Algae

Now, when I say algae, I don’t mean hair algae or other nasty looking algae. I mean a Macro-Algae such as Chaetomorpha or Caulerpa.

Algae uses nutrients to grow, one of the main nutrients it uses is Nitrate.

By setting up a refrugium or an algae scrubber, every time you harvest the algae you are physically removing a great big lump of Nitrate.

You will need a grow light of some kind, which will have an additional electrical cost.

1. Nitrate Reactors

Nitrate Reactor

Though this is the most expensive means of removing Nitrate on this list, it is also the easiest & most effective way. Buying a piece of equipment that is purpose built to help reduce nitrates will be more efficient than trying to do something yourself. It will also help reduce the chance of you making a mistake and causing a bacteria bloom in your aquarium!

By creating an anaerobic chamber inside a reactor, a colony of nitrate-consuming bacteria is established on the media that is placed within it. As the bacteria grows, your nitrates will lower.


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