Bring water to a hard boil in an 8 to 12 quart crock pot.
NOTE: You will need room in your freezer for this or at least two gallon size pitchers.
Add Jello and sugar and stir till completely dissolved.
Mix in both juices and rum.
NOTE: If these ingredients are pre-chilled it will speed the cooling process in case you're short on time.
Place the whole thing in the freezer.
NOTE: The alcohol and jello will prevent it from freezing solid so it can safely be left for hours, even overnight.
When ready to serve pour into large punch bowl and slowly add the ginger ale. Stir very gently to mix.
OPTIONAL: Fill a bowl just a little smaller than the mouth of your punch bowl with water and freeze. This works better than ice cubes because it melts more slowly it won't dilute the punch too much. When ready to serve the punch rinse the the outside of the bowl your ice is in with hot water till it comes free. Place in the punch bowl. To make it pretty I like to put slices of fruit on top once it's all in place. (Oranges, lemons, limes, kiwis & strawberries are some that I've used.) They'll freeze to the surface and stay put. You can even rinse the ice float off after the party and save it for another time.