I've been reading about lowering soil pH and it's been confusing so far, I bought some aluminum sulfatet thinking it should be a good way to lower it. I'm keeping all my growing organic and after reading it can be toxic to humans i'm looking for some advice on it. I bought a garden mix from a local supplier that consist of brown sandy loam topsoil, aged leaf compost, mushroom compost and cow manure for my raised beds. The pH is reading about 8.0 obviously too high for the peppers and tomatoes I'm growing. What is the best way to lower my pH? I'm already noticing plants having a deficiency in nutrients with yellowing of the leaves.