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Cycle Chemistry

Nitrate (NO3-)

The end product of the nitrogen cycle - much less toxic than ammonia or nitrite but still stressful at high levels.

Unit: ppm Code: NO3

📊 Ideal Ranges

Freshwater
0-40 ppm
Saltwater
1-10 ppm
Reef
1-5 ppm
Planted
10-30 ppm

📖 Overview

Nitrate is the byproduct of complete biological filtration. In freshwater fish tanks, keep under 40 ppm. In reef tanks, 1-10 ppm is ideal - too low starves corals; too high fuels nuisance algae. In planted tanks, 10-30 ppm actually benefits plant growth. The only reliable way to remove nitrate is water changes or specialized reactors.

📉 How to Lower

Water changes (still the best method). Live plants (nitrate = fertilizer). Refugium with macroalgae (reef). Deep sand bed anoxic zones. Vodka/vinegar dosing (advanced reef). Nitrate reactors.

🐟 Species with Specific Requirements

Threespot barb
Enteromius trimaculatus
aquarium
Tetragonopterus chalceus
Labeobarbus Wurtzi
Labeobarbus wurtzi
aquarium
Buccochromis spectabilis
Victoria tilapia
Oreochromis variabilis
Lethrinops Microdon
Lethrinops microdon
Sharpbelly
Hemiculter leucisculus
aquarium
Hemigrammus rodwayi
Pike cichlid
Crenicichla johanna
Kyushu bitterling
Rhodeus atremius
Mřenka Luopingská
Yunnanilus macrogaster
Mesopotamian Pike Chub
Squalius lepidus
Bushymouth catfish
Ancistrus dolichopterus
Peixe-dourado
Glanidium albescens
aquarium
Acaronia vultuosa
Zebra lampeye
Hypsopanchax zebra
Blackspotted nothobranch
Nothobranchius melanospilus
Bryconamericus Carlosi
Bryconamericus carlosi
aquarium
Auchenipterus nuchalis
Chromidotilapia Regani
Chromidotilapia regani
Parecbasis Cyclolepis
Parecbasis cyclolepis
Kura nase
Chondrostoma cyri
Betta Falx
Betta falx
Leporacanthicus Heterodon
Leporacanthicus heterodon
Royal tetra
Inpaichthys kerri
aquarium
Naevochromis chrysogaster
Softy hap
Mylochromis mollis
Thinface cichlid
Serranochromis angusticeps
Leopard corydoras
Corydoras julii
Pseudohemiodon Thorectes
Pseudohemiodon thorectes

🔗 Related Parameters

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Ammonia (NH3/NH4+)
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Denitrification
The anaerobic bacterial process that converts nitrate into harmless nitrogen gas...
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New Tank Syndrome
The predictable ammonia and nitrite spikes that kill fish added to un-cycled tan...
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NH3 vs NH4+ (Ammonia Chemistry)
The critical distinction between toxic un-ionised ammonia (NH3) and less toxic i...
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Nitrite (NO2-)
The second stage of the nitrogen cycle - less immediately toxic than ammonia but...
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Nitrogen Cycle Overview
The complete biological process by which fish waste ammonia is converted to nitr...