in hydro its a disaster waiting to happen imho
any sugar in your water gives nasties something to feed on
Nasties aren't necessarily nasty though.. There are beneficial bacteria/protozoa in the rhizosphere/roots that chelate and prepare/chelate various molecules for uptake..
Extended dark cycles stimulates plants like MJ to dump alot of carb reserves into the rhizosphere.. Late in the cycle these micro-organisms feed on these carbs, and penetrate the intercellular regions of the roots to put the energy to good use for the plant..
Essentially the carb loading from molasses isn't for the plant directly, plants can't uptake complex molecules through the xylem.. You're actually feeding your helper organisms so they can do more good for your plant..
At the concentrations we're talking, that won't gunk anything up, but you can reduce the amount of simpler sugars like sucrose in molasses if you want by mixing molasses with warm water really well, then letting that sit undisturbed for a couple days.. When it settles you will have an amber like liquid up top that contains simple easily fermentable sugars, and in the silt layer will be all the complex stuff.. Honestly though I don't know if thats beneficial here or not.. Distillers use that trick to get higher concentrations of fermentable sugars.. For this though I think the total package may be best..