Hello, I have been reading a lot of the posts and have a few questions.
I have 6 citrus in different size containers ranging from 5gal to 45 gal.
I have a few questions about using this fertilizer. First I want to know if anyone knows whether it contains calcium?
My second question is regarding amounts. I apologize in advance if this sounds stupid, but I am really new at this and I am a little confused with certain things.
I know that the recommended amount is 300 ppm with every watering, which comes out to be .9 teaspoon per gallon. My question is:
Does this mean that if I have a 15 gallon container with a meyer lemon I have to use 13.5 teaspoons of this fertilizer? If that is the case do I also have to use 15 gallons of water with it or can I mix it all in one gallon of water and then maybe use the hose to finish it up? If not, what is the correct way and amount of using this fertilizer?
Thanks in advance.

No, you do not change the concentration of 300 PPM (.9 tsp). No matter what the size of the container is, the .9 tsp. per gallon always remains the same. Just apply the fertilizer solution to the surface of each container, until approximately 10 percent of the liquid drains out the container's bottom. If you are growing your trees in a rapid draining medium, such as a medium that contains mostly CHC or bark, where the fertilizer or water solution passes through the medium so rapidly that it does not time to absorb into the medium, you can soak the tree's root system by immersing the container into a larger bucket full of the water or fertilizer solution for two minutes. When your tree is soon to be in flower, (spring), you might want to reduce the fertilizer concentration to 250PPM. NOTE: Whether you fertilize with every watering or not depends on the medium you are using and how rapid it drains. - Millet (1,068-)

Thank you so much for answering so quickly Millet.
So if understand correctly, I should mix .9 tsp of the fertilizer into a gallon of water and pour it on top of the containers whether it's 1 gallon or 100 gallons size container and then let 10% of it drain out?
So if I have 6 trees I should mix this .9 tsp 6 different times...right?

Marce, your assumption is correct. I have 100+ citrus trees. Most are in containers, but 7 of the trees are planted directly in the ground. I use a 55-gallon drum, and make 55 gallons of 350 PPM fertilizer at a time using a 25-5-15 W/ trace minerals fertilizer formula. I also add a little Epsom salts. I then go around applying some of the fertilizer solution to all of my containers, plus the in ground trees. - Millet (1068-)