Watering with lime and epson

I find that if I mix other things like lime and epson, the drainage decreases considerably than if I just use the mix out of the bag. I think it's because the peat and wetting agent brakes down when I handle it, making the soil more compact. Anyway, how much of a difference dosage wise should it be between, watering with lime, and mixing it into the soil from the beginning ? I'm guessing using more would be better because some of it will be lost in the runoff, but I am unsure.