Will a solution of ground phosphate and bleach kill the hanging moss in my oak trees without damaging the lawn

St. Augustine gr, the owner does not want to harm the trees. physical removal has proven tedious, also the moss is a nuisance to the underlying landscape. the trees are showing epiphytic stress due to the lack of available moisture. the trees are of historical value and we do not wish to trim them for some time. We're talking a lot of moss here people. Surely there is some place I can turn it in at to attain a small profit. I am in Lake county, Fl.. Also, I believe that there is a method that could be achieved with a pressure washer as a delivery mechanizm for a product that won't harm the environment. I think maybe even a fertilizer that is too strong for the moss may be diluted by the time it oxidizes and reaches the ground. Yes, I know what copper sulphate is. But I believe it will harm the new growth and that any attempts should be timed seasonally to avoid this.