Pet Lobster

Question
In my looking for a non-conventional pet, I have decided to buy a pet lobster.  I am aware that they may grow 40 lbs and up to three feet as I am also aware that growing requires a large enviornment.  
That said, I am wondering as to certain aspects of the lobsters enviornement and I was hoping you could help me with these questions.
I do not plan on going exotic, I am going to buy a lobster from the local food store.

What should the PH of the water be?

How can I determine salt content?

How frequently should the water be changed?

What does a lobster eat?

Is there a certain temperature my water should be kept at?

Is there a certain system I should use as an aquarium?

And about how long is the Lobster's growth process, I mean to the point where he is noticably large?

I would appreciate any reply.  Thank You.  Patrick.

Answer
Patrick,

I feel bad that I can not really answer any of your questions with 100% conviction. I can answer these based on my salt water fish knowledge.

1.  ph should be 7.8 to 8.1
2. salt content should be tested with a hydrometer.  specific gravity should be 1.021 to 1.025
3. water changes should be done on a weekly basis about 10-20%
4.  water should be be cold I am not sure the exact temp.
this is all I really know.
I hope it helps
Todd