Test Your Aquarium Water: pH, NO3, CO2 and More

Why Test Aquarium Water?

Testing water is essential to maintain a stable environment. It helps prevent diseases, promote plant growth, and keep fish healthy. Imbalances in nitrites (NO2), nitrates (NO3), or unsuitable pH can quickly become problematic.

Essential Parameters to Monitor

• pH: Measures water acidity. Should be adapted to your species (usually between 6.5 and 7.5).
• GH (General Hardness): Indicates water mineralization. Essential for invertebrates and some plants.
• KH (Carbonate Hardness): Stabilizes pH and enables good CO₂ regulation.
• NO2 (Nitrites): Very toxic, must be at 0 mg/L.
• NO3 (Nitrates): Should be kept under 50 mg/L, ideally around 20 mg/L to prevent algae.
• CO2: Fundamental for plant photosynthesis. Too much or too little can disrupt the whole ecosystem.

Test Strips or Drop Tests?

Test strips are convenient and quick, ideal for regular monitoring. However, their accuracy can be insufficient during imbalances. Drop tests offer better reliability, especially useful for precisely adjusting CO₂ or fertilization doses.

Recommended Testing Equipment

JBL Drop Tests

Precise tests for pH, KH, NO2, NO3, CO₂...

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Average cost: €50

Test Strips

Ideal for quick checks of pH, GH, NO3, Cl2...

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Average cost: €15

Digital Tests (CO₂ and Temperature)

Continuous display of CO₂ levels and temperature.

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Average cost: €50

Practical Tips

• Always perform tests at the same time (preferably in the morning).
• Use a notebook or app to track parameter changes.
• Change water if NO2 > 0 or NO3 > 50.
• Avoid overfeeding fish, which increases nitrogenous waste.