Typically guano is added to soil along with other amendments and beneficial fungi and effective micro organisms and left to cook for around 6 weeks. This gives the guano a chance to break down and become useable to the plant. If you want to supplement your soil mid grow, There are some liquid forms that are already chelated that you can use. Or you could make an aerated compost tea with the guano in which you would place it in water with an air pump and stone add some em-1, and molasses and give it a few days at about 74-76 degrees. When a nice thick foam forms on the top the tea is ready to be fed to the plant. When using organic mediums you certainly can make things too strong and burn them, however when properly done the plant will use what it needs when it needs it, no need to buffer ph as organic substrates do this on their own. Hope this helps. Green mojo.