Honey ferments easily, and can cause sores in a hummers mouth.
Artificial sweeteners have no food value. DO NOT use red food coloring in your solution, as this could be harmful to your hummers. No testing has been done on the effects dye has on birds. Most feeders have red on them and that should be enough. If you see black spots inside your feeder this is mold and you will need to scrub it out with a good bottle brush, but if you can't reach it with a bottle brush you can add some sand with water and shake the feeder to remove the mold.