What is the deal with the different ratio of syrups? I've seen it mentioned a 1:1 and 2:1 and so on. Is this syrup that you make yourself with granulated sugar? If so how is it made and when do you use 1:1 and when do you use 2:1? Also, I've heard that you don't want to leave the syrup in the feeder too long. How long is too long?