Place 9"x12" metal cake pan in freezer to pre-chill. (This also allows for you to clear room for the pan as well).
Place 6 cups of water in pot with 1 cup of Splenda. Bring to a simmer allowing the Splenda to dissolve.
Remove the pot from heat and allow to cool while stirring in the 1 cup of lemon juice, 3/4 cup pineapple juice, and 1/4 cup lime juice to the pot.
Pour the liquid into the pre-chilled cake pan and place in freezer. Check every 30-45 mins 3- 4 times and scrape ice that is forming off edges into the center.
Once I get a slushy ice mix I pour the mixture into saved 4 oz. Luigi Italian Ice containers. This mixture produces about ten 4 oz. cups. I then cover each individual cup with freezer press and seal wrap. Then I place the cups back into the cleaned out cake pan to place back into the freezer until l they freeze solid.