Molasses is more of an additive for organic soil grows,even though I believe it can be used in other mediums. It's used to feed the beneficial organisms in the soil mostly, but also adds some trace elements. I use an unsulfered blackstrap that has high levels of calcium and magnesium. I've never done side by sides with/without, I'd bet someone here has, but I've never seen any negative effects from it. I'm outdoors btw.