Sacrifice Anode and a new Anode

In February 2014, my 2001 Rheem 11108007 80l 3.6kw Hot Water System began to leak. This had replaced a hot water system that I had inherited in 1996.

1996-2001 = 15 years
2001-2014 = 13 years

Reading the manual of the 11108007 Model, with hindsight - page 5 says The suggested time after installation when the anode should be inspected is Rheemglas 8 years and Optima 10 years. C'est la Vie!

The new hotwater system, which was installed on 14 February 2014, is a Rheem 191050C7 50l 3.6kw model. The manual of the new Hotwater system says the system should have a five year service, which includes inspecting and replacing the Anode.

However, by early June the Hot Water system was making a lot of noise when it was heating up and the hot water came out in spurts. I know now that these are the symptoms of a used up Anode!

Ofcourse, the question is whether I left it too late and that the system has begun to rust already.