Just mix up a sugar water solution at home - 4 parts water to 1 part white sugar. This is about as close as one can get to natural flower nectar and is infinitely less expensive than buying a purchased solution.

It may take your hummers a few days to get used to a different fomulation.......but they will. It could also be that your hummers have started their reverse migration, depending on your location, and that's why you have fewer visiting.

Wow, that's odd. Oriole nectar is generally a 6-1 mix. Hummers on a diet, or is there something other in the Oriole nectar?

I do the 1-4 sugar water mix and I have 3 or 4 regular customers daily and they return year after year :) The dye in the store bought stuff is actually not recommended by bird experts.
https://journeynorth.org/tm/humm/food_red_dye.html