That's a trick florists use to prolong their cut flowers. Very diluted Sprite, 7-Up, and Ginger Ale work too. It seems that the soft drink dilution was 1 tsp. per quart. I don't remember the sugar but if I had to guess, it would be 1 tsp. per gallon, just like most water-soluble fertilizers.
SuperThrive used to advertize that it was good for everything, and I do mean everything. Have a fungal, bacterial, viral problem? Use SuperThrive. Plants not doing well (regardless of the reason)? Use SuperThrive. Though I have it, I seldom use it. It does perhaps help with shock and stimulates rooting when transplanting, but I really don't know. Someone on NGA uses it to soak her seeds before planting and says she gets good results.