💧 Poor water quality in freshwater aquariums – causes, solutions and how to keep it stable long-term
Share
🌿 Why water quality is so important
Water is the heart of your aquarium – it's the habitat, food source, and environment for all the animals and plants. If the water parameters are out of balance, this can quickly lead to algae problems, diseases, plant death, or even fish losses .
Many aquarium owners rarely or never measure their water parameters – but this is precisely where the root of many problems lies. Understanding which water parameters are important and what influences them will allow you to keep your aquarium healthy and stable in the long term.
🔍 The most important water parameters at a glance
| Water quality | Optimal range | Meaning |
|---|---|---|
| PH value | 6.5 – 7.5 | Indicates whether the water is acidic or alkaline. |
| KH (carbonate hardness) | 4 – 10 °dKH | It stabilizes the pH value and acts as a buffer. |
| GH (Total Hardness) | 6 – 14 °dGH | Important for mineral balance and invertebrates. |
| Nitrite (NO₂) | 0 mg/l | Highly toxic – must be undetectable. |
| Nitrate (NO₃) | 10 – 25 mg/l | Plant nutrient – too much promotes algae growth. |
| Phosphate (PO₄) | < 0.5 mg/l | Important plant nutrient – too much promotes algae growth. |
| Ammonium (NH₄) | < 0.2 mg/l | Precursor of nitrite – too much is toxic. |
🧪 Causes of poor water quality
🍤 Overfeeding
Too much feed → too many breakdown products → rising nitrite and nitrate levels
🪵 Overstocking
More animals = more excrement = higher pollution levels
💧 Infrequent water changes
Nutrients and pollutants accumulate
🧼 Insufficient filtering
Toxic substances are not broken down sufficiently.
🌿 Too few plants
Reduced nutrient consumption → algae and imbalance
✅ Step-by-step: How to improve your water quality
💦 1. Perform regular water changes
Perform weekly water changes of 20–30% . This dilutes pollutants, removes waste products, and provides fresh minerals.
🧪 2. Test water regularly
Check all important parameters with drop tests or test strips . Only when you know what's wrong can you react appropriately.
👉 In our shop you will find high-quality water tests and care products to help you keep an eye on your aquarium.
🍽️ 3. Adjust the amount of food
Feed only as much as your animals can eat in 1-2 minutes. Excess food is a major source of nitrate and phosphate.
🌿 4. Use plants strategically
Fast-growing plants such as elodea, hornwort, or hygrophila absorb excess nutrients and help to lower nitrate and phosphate levels.
🪸 5. Use beneficial invertebrates
Snails and shrimp contribute to biological stability by consuming leftover food and biofilms, thereby reducing degradation products.
👉 In our shop you will find a selection of invertebrates that not only keep your aquarium clean, but also support the ecological balance.
🧼 6. Don't forget filter maintenance
A dirty or improperly cleaned filter can destroy bacterial cultures. Always rinse filter material in aquarium water , not tap water.
🧠 Prevention: How to keep water quality permanently stable
-
💧 Change the water weekly
-
📊 Measure and document regularly
-
🍤 Adjust the amount of food
-
🌿 Increase plant diversity
-
🐌 Use beneficial invertebrates
-
🧼 Perform filter maintenance regularly
✅ Conclusion: Healthy water parameters are the key to a stable aquarium
Good water quality isn't a matter of chance – it's the result of regular maintenance, targeted monitoring, and biological balance . By keeping an eye on it and reacting promptly, you create a stable, healthy environment for all animals and plants.
👉 Discover water tests, care products, invertebrates and accessories in our shop now, with which you can keep your water parameters optimally stable.