Drain the Sediment
Sediment and sludge from the minerals found in hard water will collect at the bottom of the tank. The sediment can be corrosive, which will lead to rust and a possible leak. The inside of the tank is glass lined to help prevent corrosion, but it is common for there to be an imperfection in the liner. Unfortunately, you will not know about any imperfections in the liner or corrosion until it is too late.
To help prevent a possible leak and improve operating efficiency, drain the sediment from the tank. Start this process while you have the cathodic anode rod removed and the power is off. Dump a citric-acid-based cleaning product into the tank and let it sit overnight to let it loosen up the sludge. Don’t use the hot water during this period.
Attach a garden hose to the drain valve and place the other end in a bathtub or outside. Slowly open the valve as to not stir up the sediment at the bottom of the tank. It is best to have a partner at the other end of the hose to check the color of the water. It will most likely start out as a yellowish color and slowly become clear. Close the drain valve and remove the garden hose at this point.