If it sits and a layer forms and dries, this slows fermentation. In wine making this layer is called the cap, and as in wine making I have taken to "punching the cap" on a daily basis. What I have seen when using kelp and alfalfa meal is when entering the lactic or malolactic phase of fermentation (forgive me my terminology may not even be correct here), but at any rate the bulk of sugar is used up and the cap will fall. This means the floating layer will sink either partially or all the way. This indicates a bulk of the "easy" fermentation is done and in wine the process of racking and aging begin. To me the ucf uses too much sugar imo if you are buying high brix molases (I do) that is enough, If the fruits and such are organic or beyond organic and are not going to be eaten, then by all means use those. Green manures, mulching, composting and fermenting is where its at and where its been at for a long time, some articles I've seen dating back to 1800's and incorporating mineral salts too. We have lost the best ways to micromanage our environment.....