Build up of nitrogenous waste, detritus, and impurities in an aquarium cause fish to stress and can lead directly to disease and possibly death of your aquatic wildlife. An aquarist’s understanding of the nitrogen cycle is key to maintaining a healthy aquatic environment.
1) Nutrients entering your aquatic setup are the beginning of the nitrogen cycle. Nutrient contributing factors are fish population, feeding, dead and dying plant matter, terrestrial contaminants (e.g. snails, slugs, and insects), and a variety of airborne contaminants (e.g. dust, leaves, and insects).
To measure nutrient levels in an aquarium or pond you will want to find a test for Nitrate (NO3). Below are some products Happy Fish uses to test for this nutrient.
Amazon link to API Nitrate Test Kit. This link also provides for the purchase of several other types of test kits offered by API.
2) The natural decomposition of nutrients turns directly into ammonia, a toxic component to wildlife.
In a fully cycled aquarium or pond the bacteria detox the ammonia very quickly but some situations can cause an increase in Ammonia that can end up being toxic to the wildlife. There are products that can reduce the excess ammonia build up.
Amazon link to Fluval Ammonia Remover, 180-gram nylon bag, 3 pack.
Amazon link to Fluval Ammonia Remover, 1600-gram or 2800-gram.
Amazon link to Kordon Amquel Plus, 8-ounce.
Amazon link to Kordon Amquel Plus, 16-ounce.
Amazon link to Kordon Amquel Plus, 1-gallon.
3) The heart of the nitrogen cycle are nitrifying bacteria which convert ammonia to nitrites.
Freshwater species: Nitrosomonas sp.
Saltwater species: Nitrosococcus sp.
Nitrites are considerably toxic to wildlife and plants.
Similar to Ammonia, Nitrite will typically never reach toxic levels in a fully cycled aquarium or pond. However, there are situations that can lead to a toxic increase and can be deadly to wildlife.
Amazon link to API Nitra-Zorb Filter Media Pouch, size 6, single or 2 Pack.
4) Then additional species of nitrifying bacteria convert the nitrites to nitrates.
Freshwater species: Nitrobacter sp. & Nitrospira sp.
Saltwater species: Nitrococcus sp.
The nitrates are toxic in extremely high concentrations but are also an excellent aquatic and terrestrial plant food.
To properly ensure the aquarium, fresh or saltwater, cycles completely with all the necessary nitrifying bacteria, in a shorter period of time, use this product:
Amazon link to API Quick Start Aquarium Nitrifying Bacteria, 4-oz, 8-oz, 16-oz, & 32-oz, Freshwater or Marine.
5) Nitrates accumulate in your aquarium but there is a limited amount absorbed by live plants (freshwater) or corals (saltwater). In a saltwater setup there is an additional step in this cycle called denitrification. At this stage there are bacteria that will break down the nitrate back into nitrogen gas and water.
A way to remove excess nitrate build up would be to perform a water change but in some situations the increase of Nitrate exceeds the reduction a routine water change would remove. In this case it is not recommended a larger water change occur because this could change water chemistry enough to endanger the health of the wildlife. Therefore it is encouraged that a product that helps remove nitrate be used in addition to the normal routine water changes. Some nitrate removers are in liquid form and can be used on a periodic basis while others are a resin that can be added to the filtration system using a nylon mesh filter bag. With this type of nitrate remover once it has absorbed all the nitrate it can, the bag can be removed, and can be regenerated to use again when needed.
Amazon link to South Ocean Five 8″ x 12″ Nylon Mesh Bags, drawstring.
Amazon link to South Ocean Five Nylon Mesh bags, various sizes.
6) As the nitrate level increases, so does algae growth, taking away from the beautiful aesthetics of your aquarium. If you need further understanding of algae, please refer to… Dealing With Algae: Freshwater.
7) Gravel vacuuming (freshwater aquariums and ponds only) combined with weekly to bi-weekly water changes will keep excess nutrient levels down in your aquarium.
Amazon link to Lee’s Mini Economy Gravel Vacuum.
Amazon link to Lee’s Regular Economy Gravel Vacuum.
Amazon link to Lee’s Large Economy Gravel Vacuum.
Amazon link to Lee’s Ultimate Gravel Vacuum, 25-feet.
Amazon link to Lee’s Ultimate Gravel Vacuum, 50-feet.