depending on your hydro i wouldnt use molasses. i dont know about other systems but i imagine its similar, i ran an ebb and flow and used molasses for the last couple of weeks and it fucked with my system. the res got all gross around the edges and there was a film at the top of the res, and it attracted aphids to my plants. it might clog your tubes if you run a drip system. im sure there are substitutes for a molasses in powder form like carb boosters or something.