Very interesting idea. With the added of laboratory support to understand concentration levels, you would have to experiment with dilution ratios.
Maybe you would start with one tablespoon dissolved in 8oz of boiling water. Then maybe dose @ 1 drop per gallon in your test tank. For the test to be fair you need two identical tanks, a test and a control tank.
I'm very interested in the all organic approaches. If you decide to move forward please consider a journal.
If it were up to me, I'd cut dividers out of plexiglass to split the tank up into 64 sections, and lay out the controls in a Latin Square to minimize parametric noise. With around 20 runs or so, it'd be pretty close to having publication quality data. (With only two comparisons, your results will be no better than anecdotal) Put in an equal amount of plant mass into each section and then weigh what comes out at the end. Something that's easily friable, like moss would probably work best. You'd have to make sure you standardized your water between runs to control for fluctuations in trace elements and mycorrhizal flora in case you're using vascular plants as your test organism.
As for standardizing the active ingredient concentrations- you could determine maltose concentrations fairly easily in a Gas Chromatograph. Many local testing labs (i.e. drug testing) would probably do this for you at around $30 a sample. I wouldn't bother with less than three samples a shot, with one of the samples having an already known concentration as a check to make sure the lab is actually doing the testing properly.
That said, comparative saccharide utilization has been thoroughly hammered out with the advent of radiolabeling in the 1930's, 1940's, and 1950's. Most any textbook on general or plant biochemistry (e.g. Lubert Stryer), botany (e.g. Peter Raven) or a review article (e.g. Berg et. al.) should have the information the original poster is looking for. Failing that, a google DOI search or book search (Try: light independent Calvin Cycle reactions) would probably turn up similar results.
When it comes to chelation of oxidized transition metals at physiological pH, polysaccharides (which are weak poly-alcohols) are orders of magnitude less efficient than weak ionized organic acids like citrate or butyrate. Any appreciable chelation effects from blackstrap molasses probably has more to with stabilizing agents (commonly Ascorbate or EDTA in food) and breakdown products of molasses than the actual molasses itself.