This might be a dumb question, but does spraying your plants with some kind of ewc/compost/kelp solution leave behind any spots or residue on the leaf surface after it dries? Or do you find that this is not the case.
It acts as a surfactant but be careful because they also have oil and grease detergents in them. Specific ones don't.I put a drop of dish washing liquid per litre. I read this is a wetting agent which supposedly makes the droplets smaller or something.
Reason I have seen people worry about foiler feed in flower is bud rot and PM. I always add extra fans after foiler to prevent any fungus or water sitting where the large fan leaves meet the stalk. The dish soap is a surfactant. I was reading up on surfactant and really like Dutch Masters Saturator for this purpose as it says it will carry proteins, complex carbs and amino acids to pass through directly into the plant cell beyond the outer layers. "transport large molecules through the Plasma Membrane".I use Dutchmaster Saturator and Liquid Light.