I surely wouldnt use molasses in a hydro setup...
what it does is pretty much activate bacterias and such in your soil (Its kind of like using enzymes..) except it will also bring a calcium and magnesium amendment.... and flavor......
Its a very very thick syrup it does dilute in warm water... but if you were to let it sit for a long time, it would all just sink to the bottom and stick together again...... so if you dont wanna take chances clogging your hyrdo system i wouldnt do it.... If you want your plant to uptake nutrients a bit faster (which isnt really worth it in hyrdo) try enzymes, and if you want the "flavoring" of the molasses try fructose.... I believe you can find pretty liquid fructose which isnt syrupy and dont stick so much...
Hope this helped you make a decision
till then,
Keep it green in love and under JAH LIGHT