Let's Go Sky Pony!

In 1995 I bought a water heater and put it in my house. It still heats water fine but when you turn on the hot water, it comes out fast the first few seconds then it slows down to a trickle. I think it's full of sediment like calcium and lime. I tried backwashing it, made a lot of noise but it didn't help. I guess it's time to get another one, 13 years isn't bad. The name of the tank is Service Star, my tooth brush is named Sky Pony.