💧 Water changes in aquariums – why, how often and how much?

🌿 Why water changes are so important

Water is the heart of your aquarium – it's a habitat, a nutrient carrier, and a waste disposal system all in one. 🐠 Without regular water changes, this delicate system can quickly become unbalanced. Pollutants accumulate, algae grow faster, and fish or invertebrates can become ill.

Many beginners underestimate the importance of regular water changes. This article explains why they are so crucial, how often you should change the water, and how to do it correctly.

🧪 Why a water change is essential

Biological "waste" is constantly produced in the aquarium:

  • 🍤 Leftover food

  • 🐟 Animal excrement

  • 🌿 Dead plant parts

  • 🪱 Bacterial degradation products

These substances lead to an increase in nitrate and phosphate – nutrients that, in large quantities, promote algae growth and put a strain on animals. At the same time, plants and microorganisms consume important minerals.

👉 Only by regularly changing the water can you remove these substances and simultaneously introduce fresh minerals and trace elements.

📆 How often should you change the water?

The frequency depends on the size of the aquarium, the number of fish, and the filter performance. However, for most freshwater aquariums:

  • 💧 Change 20–30% of the water weekly

  • 🐠 In case of heavy stocking or algae problems: 2x per week approx. 20%

  • 🌿 For planted aquariums or shrimp tanks: regularly, but moderately

💡 Tip: It's better to perform small water changes regularly than large ones infrequently.

📊 How much water is ideal?

Adding too much water at once can be harmful, as it leads to sudden changes in water parameters. The rule of thumb is:

  • 🔄 20–30% per week → optimal for most pools

  • 🧪 In case of high nitrate levels: change up to 50% of the water , but gradually.

🪣 Step-by-step instructions: How to perform a water change correctly

🧼 1. Preparation

  • Turn off the filter and heating

  • Provide fresh water (same temperature as in the aquarium)

  • Treat it with a water purifier to remove chlorine and heavy metals.

👉 You can find water conditioners in our shop – they make tap water aquarium-friendly immediately.

💧 2. Vacuum out the water

  • Remove 20–30% of the water using a hose or gravel vacuum.

  • Vacuum up detritus and leftover food from the substrate.

💡 Tip: Especially in areas with little current, a lot of organic material often accumulates.

🌿 3. Add fresh water

  • Pour in the new water slowly to avoid stressing the animals.

  • Then check the temperature and water parameters.

🪸 4. Follow-up check

  • Switch filters and technology back on

  • Observe plants and animals – they should appear more active after a water change.

🧠 Typical mistakes when changing water

❌ Changing the water too infrequently: Pollutants accumulate and promote algae growth.
❌ Too much at once: Sudden changes can stress animals.
❌ Do not use water without water conditioner: Chlorine and heavy metals are harmful to fish and invertebrates.
❌ Only change the water, do not remove detritus: Organic pollution remains.

🐌 Bonus tip: Water changes as part of your maintenance routine

Use the water change as an opportunity for other maintenance steps:

  • Prune plants

  • Clean the windows

  • Check filter for flow rate

  • control snail or shrimp population

👉 In our shop you will find practical accessories for water changes, water conditioners and useful invertebrates that will help you with maintenance and keep your aquarium stable in the long term.

✅ Conclusion: Regular water changes = healthy aquarium

Regular water changes are the simplest and most important way to keep your aquarium healthy, stable, and algae-free. They ensure stable water parameters, prevent disease, and support the natural balance. 🌿💧

👉 Discover everything you need for a safe and stress-free water change in our shop – from water conditioners to helpful invertebrates.

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