Gold Electroplating on Aluminium?

I want to do some gold plating, specifically on aluminium; iPhone 5 case is made of this. But, I have read that gold plating aluminium isn't simple as cleaning it and going straight into gold plating.

I think I read somewhere that process is something like: Clean it; put it in some chemical called "Zincate", or something along those lines; then a nickel coating; next copper; and then the final gold plating. Is this correct?

Also, what methods would be best for a cosmetic alteration like this: Brush and/or Tank?
I was thinking definitely tank for the final gold layer, and most probably for everything else. But, I don't know enough about to the processes to know if brush plating it would suit any of it better.

Finally, I assume the more times you use the metal solution the weaker it gets as it has less gold in it.So, what do I do about this? Do I just buy more metal solution or is there a way to replenish the metal solution to make it more concentrated, maybe from a sort of solution or with scrap metal itself (if that's how it works).

Any help on this subject will be much appreciated, and any additional info would be great.

Because aluminium is always covered with a thin protective coating of alumina is is very difficult, but not impossible to do what you are suggesting. This is discussed in detail in a paper at
http://core.materials.ac.uk/repository/eaa/talat/5205.pdf