Having successfully killed my first two orchids I recetly picked up a SLC Hsin Buu Lady. It has one open bloom with four more coming.

I have two orchid fertilizers one 20-14-13 and a bloom booster 11-35-15. I know that I need to use 1/4 the amount they say to. I am wondering are these good formulas or should I get something different?

Also if I mix a gallon is it OK to store the remainder till next time? Or should I always mix new to prevent growth in the jug?