How can I change tank water effectively and safely?

To change tank water effectively and safely, follow these steps:

1. Turn off all equipment in the tank.
2. Use a siphon or aquarium vacuum to remove about 25-30 of the water.
3. Use a water conditioner to treat the new water before adding it to the tank.
4. Slowly add the treated water back into the tank to avoid shocking the fish.
5. Turn the equipment back on after the water change is complete.