you could always just buy a bottle of a carbo nutes from the hydro shop and throw it in your res, all of them are derived from cane sugar or molasses and if you don't see a difference almost all hydro nutes come with a money back garuntee i mean you do say you get ounces every month so in 3 months you will know
I've been trying to email one company selling a carbo nutes product to see if they could refer me to a peer reviewed research paper backing up a claim that plants can uptake carbos. Of course they never answered because there is no research to support their claim (ie. it's BS).
Most of these addiditive products that hydro shops try to sell will not do what they claim. There is not a shred of evidence that plants are able to uptake sugars, vitamins etc. In fact, plants have specialized cells in their roots that target only specific mineral salts.
Don't listen to the hype of these manafactuers; if they can't point to a research paper to back their claims then it's bullshit. Most people don't pursue a money back guarantee and even if they did the manafactuer can always claim that you messed up. "Money back guarantee" should not be thought of as a slogan to establish credibility.