No, it can run off 120 also. As long you have a unit that is built that way form factory. You should be able to tell this by looking at the label on the control box.
You need a salt water chlorinator. A salt water chlorinator is an electronic devise that converts the salt in the water from the pool into chlorine gas that is then absorbed into the water.
Turn of the salt water chlorination and start adding chlorine the same as you would in an ordinary pool. The salt water in the pool will become less salty over time so you don't have to worry about changing the water. You could tidy it up a little by removing the saltwater chlorinator element or you could just leave it.
Yes, as the generator creates the sanitizer for the pool, just throwing salt in it won't do anything
Not if the pool is closed and winterized.
Yes there is no need to drain a chlorinated pool to change it to salt water pool all you have to do is add the salt install the new equipment and run it as usual.
You can vacuum a salt water pool the same way you would a non salt water pool. If you are vacuuming on the filter setting, your filter will help to clean the debris out of the pool. If you are dealing with a very dirty pool and use the waste setting, you will be wasting some of the water from the pool in the process. Depending on how much water you take out and need to refill, you will most likely need to add some salt back in to get your salt level back to normal operating levels.
Add salt
Yes as a mater of fact that is what salt water pool normally is. With a salt water pool there is a electronic salt water chlorinator installed that uses the salt in the water to create chlorine. However if you don't have a salt water chlorinator and prefer the feeling of a salt water pool then there is no reason not to add salt to the pool as well as keeping up the chlorine yourself.
two or three days a week
No. salt water is salt water. it already has salt in it
Simply put any pool can be a salt water pool, even an above ground pool.
H2O NaCl