Everything is correct. The acid protects against product oxidation. There is no need to pour in any water, and the acidity of the lemon gives guacamole a special piquancy. Although then it cannot be eaten by those who have an allegria for citrus fruits. Everything has its advantages and disadvantages.It is the acidic lemon or lime juice that keeps the avacado from turning brown. At least two tablespoons (or to taste) worth for a decent amount o guac is all you need. mix in well. Bottled or fresh, both work as long as the bottled is real fruit juice. Squeezing a couple of fresh limes is cheaper.