Wow, you actually spent money on that?
Sugar water with red food coloring is much cheaper 
Yes but it can kill the birds your trying to feed if it goes bad,sugar water shouldnt be left out more than 12 hours or you risk causing the birds to die.
The water should be boiled and the feeder sterilized everytime you set it out.
I feed hummers,they nest around my yard every year,maybe it's something in the garden that attracts them.... I always use commercial hummingbud feed as it's the safest product for them and I take it down after 24 hours and make another batch and sterilize the feeder.
