How to Change the Water in a Fish Tank?
Expert Answer
The steps for changing fish-tank water are as follows. First, prepare a clean bucket, fill it with water, and leave it in the sun for 2 to 3 days so the chlorine evaporates. Second, turn off the filter and heater, take out the stones, decorations, and fish, and set them aside. Then use a sponge or other tool to wipe the dirt around and at the bottom of the tank.
Wait about half an hour for the dirt to settle, then use a siphon to clear the debris and waste from the bottom. Finally, pour in the new water and turn the filter and heater back on to keep the water circulating. After a while, return the stones, decorations, and fish to the tank. Note that water changes should not be too frequent; usually once or twice a week is enough, and never change all the water at once, generally replacing only one quarter to one third.