The Weald Aquatics Blog - Nitrate in freshwater aquariums - another blog post from Weald Aquatics | Aquarium & Pond Fish Shop in Kent


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Nitrate in freshwater aquariums

Blog post written by Gary | 08 February 2017 | Category: Aquarium maintenance

High levels of nitrate can build up in an aquarium over a period of time and not be noticed. This can cause problems with water quality and fish health. Algae growth will be more of a problem on the plants, glass and gravel, the fish will become stressed and more susceptible to bacterial and other disease related problems.

Nitrate accumulates in the aquarium water due to the nitrogen cycle which in its simplest terms breaks down fish and organic waste into nitrate. Some of the nitrate will be will be removed from the water by vigorous plant growth, however the majority of the nitrate in the aquarium will gradually build up to excessive levels.

The quickest and easiest way to keep nitrate at acceptable levels is to change between 15% and 25% of the aquarium water weekly. This amount is dependent on the type and quantity of fish being kept. Not overfeeding and keeping the gravel and filter system clean will also reduce the amount of nitrate accumulating in the aquarium water.

There are products which will help break down the nitrate in the aquarium such as Tetra Nitrate Minus and various sludge digesting weekly treatments including Bacterlife and API Stress Zyme. These products will reduce nitrate levels, however weekly water changes are the most effective at reducing nitrate levels.

Monitoring nitrate concentration is the most effective way to keep the aquarium water parameters at ideal levels. This can be achieved using either a dedicated liquid nitrate test kit or a multi test strip.

Keeping nitrate levels at 25mg/litre or lower will not only keep the fish in excellent condition but will also not cause any undue stress in newly introduced fish.

If you want to know more, just pop into the shop and ask any of the Weald team.


An explanation of the nitrogen cycle
An explanation of the nitrogen cycle