Actually no. We had gone over this unit this past 2 weeks and that's what my organic chemistry text/professor uses. photosynthetic intermediates are the compounds that plants are able to use in their process to create the energy (sugars) that plants need. I'm still not convinced that Crypts and some other species can change it but I don't have a lab to test it unfortunately.
I had done research in the past (few months ago) for seachem excel having compounds that weren't equivalent to the CO2. I could never find the exact compounds in the excel . Otherwise I probably could have made it myself.
EDIT: Just looked at the seachem site out of curiosity... lol What bothers me is after looking at that more is that "excel also aids in reducing iron Fe3+ in to ferrous iron Fe2+)" <-- was taken from the site. Interesting stuff.
I use excel with my crypts and they dont melt maybe in a new tank. Ive grown them the same with or without excel. the excel ones are fuller and bigger but that may also be the light on that tank helping with that.