How can I change a fish tank effectively and safely?

To change a fish tank effectively and safely, follow these steps:

1. Turn off all equipment, such as filters and heaters.
2. Remove about 25-30 of the water using a siphon or bucket.
3. Use a gravel vacuum to clean the substrate.
4. Wipe down the inside of the tank with a clean cloth or sponge.
5. Refill the tank with dechlorinated water that is the same temperature as the tank water.
6. Add a water conditioner to remove chlorine and chloramine.
7. Turn the equipment back on and monitor the tank for any changes in water parameters.