Water Parameters 101

Water Parameters 101

Water may look clear, but what’s in it can make or break your aquarium. Understanding water parameters is one of the most important parts of fishkeeping — especially if you want your fish to thrive, not just survive.

This guide breaks down the most essential water parameters, what they mean, ideal ranges for tropical fish, and how to test and adjust them safely.

📊 Key Water Parameters You Must Monitor

1. Ammonia (NH₃)

What it is: Waste produced by fish, uneaten food, and decaying matter.
Safe range: 0 ppm
Why it matters: Even trace amounts can burn gills and kill fish.

2. Nitrite (NO₂⁻)

What it is: A byproduct of ammonia conversion during the nitrogen cycle.
Safe range: 0 ppm
Why it matters: Blocks oxygen in blood, causes fish stress and death.

3. Nitrate (NO₃⁻)

What it is: Final product of the nitrogen cycle.
Safe range: < 20 ppm for freshwater; < 10 ppm for shrimp or sensitive species
Why it matters: High levels stress fish and cause algae blooms.

4. pH

What it is: Acidity or alkalinity of the water.
Ideal range: 6.5–7.8 for most tropical freshwater fish (species-dependent)
Why it matters: Extreme pH can cause stress and inhibit biological filtration.

5. Temperature

What it is: Water temp based on your tank heater or room conditions.
Ideal range: 74–80°F (23–27°C), depending on species
Why it matters: Fish are cold-blooded — temp affects metabolism and immunity.

6. GH (General Hardness)

What it is: Measure of calcium and magnesium (mineral content)
Ideal range: 4–12 dGH for most community tanks
Why it matters: Affects bone growth, molting in shrimp, osmoregulation.

7. KH (Carbonate Hardness)

What it is: Buffering capacity — how well water resists pH swings
Ideal range: 3–10 dKH for freshwater tanks
Why it matters: Low KH can lead to sudden, deadly pH crashes.

🧪 How to Test Water

  • Use liquid test kits (API Master Kit is a standard choice)
  • Test ammonia, nitrite, nitrate weekly — more often during cycling
  • pH, GH, and KH can be tested monthly or when needed
  • Use digital thermometers for constant temp monitoring

🛠️ How to Adjust Water Parameters

  • High ammonia/nitrite: Water changes, Prime, reduce feeding
  • High nitrate: Water changes, live plants, reduce stock/feeding
  • pH too low: Use crushed coral or buffer
  • pH too high: Driftwood, peat, or pH-reducing products
  • Low KH/GH: Add Seachem Equilibrium, baking soda (KH), or mineral blocks

📘 Final Notes

Stable parameters are more important than “perfect” ones. Most fish can adapt if conditions are consistent. Avoid chasing numbers — instead, aim for balance, test often, and understand your water source.

Need help dialing in your tank’s chemistry? Reach out — we’ll walk you through it.