Adding coloring to nectar is just an “urban legend”; it’s never been proven to be necessary. According to Wildbird magazine, if nectar is dyed red, a typical Hummingbird (weighing just a few grams) takes in 10 times the amount of dye necessary to cause
Nowadays, almost all feeders are colorful enough all by themselves. In truth, it’s not just red that attracts them. It’s any bright color except green; (an adaptation that lets them spot nectar-producing flowers in a leafy jungle).
So please keep the nectar fresh and clear. They'll get to north Texas around the last week of March, so give them the nectar they want and need - to attract a healthy share to your yard.