NT Labs Test Nitrate (NO3) is an aquarium water testing kit used to measure nitrate (NO₃) levels in freshwater or marine tanks.

What is nitrate?
Nitrate is produced as the final stage of the aquarium nitrogen cycle when beneficial bacteria break down nitrite. Unlike ammonia and nitrite, nitrate is far less toxic to fish, but prolonged exposure to high nitrate levels can cause stress, poor health, algae growth, and reduced vitality in fish and corals. Nitrate is invisible to the naked eye, so regular testing is important to maintain good water quality.

What is the recommended nitrate level?
For freshwater aquariums, nitrate should ideally be kept below 40 mg/L (ppm). Sensitive fish species may require even lower levels. In marine and reef aquariums, nitrate levels are generally recommended to remain below 10–20 mg/L (ppm), with reef systems often targeting very low nitrate levels for coral health.

What do I do if the nitrate level is wrong?
If nitrate levels become too high, perform a partial water change to dilute the nitrate concentration. Regular maintenance such as gravel cleaning, avoiding overfeeding, improving filtration, and increasing live plant growth can also help reduce nitrate levels. In marine aquariums, protein skimmers, refugiums, or nitrate-removal media may assist in maintaining low nitrate levels.

How to use?

- Ensure the test tube is clean.
- Take a 5 ml sample of water into the test tube.
- Add the recommended number of drops of Nitrate Reagent 1 and shake thoroughly.
- Add the recommended number of drops of Nitrate Reagent 2 and shake again thoroughly.
- Wait the instructed development time, then compare the colour of the sample to the colour scale provided.
- A pale or colourless sample indicates low nitrate levels, while deeper colours indicate higher nitrate concentrations.
- Any colour forming after the recommended waiting time should be ignored.