Understanding aquarium water parameters
Water looks the same whether it is pristine or quietly killing your fish — which is why understanding aquarium water parameters matters so much. A handful of measurable values tell you everything about whether your tank is safe.
This guide explains each core parameter in plain terms: what it is, why it matters, and the range you are aiming for. Master these and you can read your tank from a test kit alone.
Étapes
Ammonia (NH3) — aim for 0
Ammonia comes from waste and is highly toxic, burning gills even at low levels. In a healthy, cycled tank it should always read 0. Any reading above 0 is an emergency.
A non-zero ammonia reading means a water change now, plus finding the cause — overfeeding, overstocking, or an uncycled tank.
Nitrite (NO2-) — aim for 0
The cycle’s middle step, nitrite, stops fish carrying oxygen in their blood. Like ammonia it should read 0 in a cycled tank. A spike means the cycle is incomplete or has crashed.
Nitrate (NO3-) — keep it low
Nitrate is the cycle’s safer end-product but still stresses fish when it builds up. Keep it below roughly 20–40 ppm; water changes and live plants are how you control it.
pH · 14 days7.9target 7.8–8.4pH — stable matters more than perfect
pH measures how acidic or alkaline the water is. Most community fish accept a broad range; the bigger risk is a sudden swing. Aim for stability over chasing a specific number.
GH and KH — hardness and buffering
GH (general hardness) is the mineral content fish and plants need; KH (carbonate hardness) buffers pH against crashes. Low KH lets pH swing — match both to your species.
Log water testpH8.1Ammonia0.0Nitrite0.0Save readingTemperature — steady and species-appropriate
Most tropical fish want a stable 24–27°C (75–80°F). Hold it steady with a heater and thermometer; rapid changes stress fish and invite disease like ich. Aquairi can track both the tank’s water temperature and the room (external/ambient) temperature, so you can see when a cold room or summer heat is pulling the water with it.
Questions fréquentes
Ammonia 0, nitrite 0, nitrate under ~40 ppm, a stable pH suited to your fish, and a steady temperature around 24–27°C for most tropical species.
GH is the dissolved minerals (calcium and magnesium) fish and plants use. KH is carbonate hardness, which buffers pH and stops it crashing. They measure different things.
Not necessarily — many fish tolerate a range. A sudden swing is far more harmful than a steady high or low value, so prioritise stability over a “perfect” number.
Do larger or more frequent water changes, feed less, avoid overstocking, and add live plants. Plants consume nitrate directly, easing the burden between changes.
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