It does not disturb the aquarium layout.
Partial Water Changes need to be done once in a week.
Partial Water Change involves replacing a portion of the water with fresh water.
The Steps involved in Partial Water Change are
1. Switch off lighting and other electrical appliances connected to the aquarium.
2. Remove about 25% of the water in the aquarium using a siphon (A special aquarium siphon can be used if available)
3. While removing the water, you can also use the siphon to vacuum aquarium substrate and remove decaying detritus, uneaten food and fish waste.
4. Now that the water has been removed, pour the new water into the aquarium using a funnel.
5. Pour the water so that you do not stir up the sediment or disturb the aquarium arrangement.
6. Switch on the electrical aquarium appliances such as the filter, lighting, etc.
Partial Water Changes also need to be done in case of emergency such as disease. In such cases, about 50% of the water may have to be replaced. Medication should also be added.
Ensure the the fresh water used is free of chlorine and chloramine.
Partial Water Changes also need to be done to reverse accidental overdose of medication.