Nitrate

From The Aquarium Wiki

(Redirected from Nitrates)

1 What is Nitrate?
2 Recommend level
3 Lethal dosage
4 Testing for Nitrates
5 Preventing Nitrates
6 Adding Nitrates
7 Links

[edit] What is Nitrate?

Nitrate (NO3) is a toxic byproduct of the nitrifying bacteria (Nitrospira) in a filter or substrate consuming Nitrite. It was previously thought species of Nitrobacter did this. but since 1998 it's considered to be species of Nitrospira).

Nitrate is less toxic than nitrite and much less toxic than Ammonia.

Nitrate damages aquatic animals in reasonably high levels of over 30 mg/l (ppm). It inhibits growth, impairs the immune system and cause stress.

[edit] Recommend level

Its normal for nitrate levels to rise slowly in an unplanted aquarium. The average safe level is considered to be under 25mg/l (ppm). Though some species (Discus for example) will only tolerate lower levels. Marine fish often need levels to be kept well below 20mg/l (ppm).

[edit] Lethal dosage

100mg/l plus is considered lethal. Though species vary in their tolerance.

Fish can withstand quite high dosages of nitrates as long as the build up of the chemical is slow and over many days.

It's quite common for less experience aquarists to go and introduce a new fish to their seemingly healthy tank of fish only for the new fish to die over night due to nitrate posioning.

[edit] Testing for Nitrates

There are many test kits available from pet shops for testing the level of nitrate in water. Some are simple strips of cards which you dip into water. Other more accurate ones use drops of chemicals you mix with a sample of water.

Aquarists should always have a test kit on hand. If there is an unexplained death or behaviour in the tank then an immediate test of nitrates, nitrites, etc. will be required as soon as possible in case action needs to be carried out.

[edit] Preventing Nitrates

If levels are not going down then you may need to do several things:

Do regular weekly water tests so you are not caught unawares.
Do a water change. By simply performing a 25% water change once a week, most tanks will remain under the recommended level.
Check the nitrate level in your tap water. Some freshwater suppliers may supply tap water to you with a high level of nitrate already!
Add a few fast growing plants to the tank. Aquatic plants consume nitrates as its one of their nutrients. Though they may also need other nutrients in order to remove nitrates. See PMDD.
Reduce feeding, you may be overfeeding the animals.
Do not overstock your tank. Remove some animals if need be.
Add a chemical treatment that removes or neutralises the nitrates.
- Prime by Seachem neutralises nitrates.
- NovAqua+ by Kordon reduces nitrates.
- Nitrateminus by TetraAqua
Add a nitrate reactor which removes the nitrate by chemical or bacteria process.

[edit] Adding Nitrates

In a well planted tank with a good CO2 supply, the plants will consume more nitrate than there is in the water. In these cases it is often the case that aquatics add nitrate via chemical powders.