Hi, and first of all I hope that you feel better soon! As for Easy Carbo, Excel and so forth, they don't truly raise CO2 levels. I once dumped about 8 ounces in my quarantine tank and the drop checker never budged. It's complicated but just do a site search for "glutaraldehyde" and there are plenty of debates on what it and does and doesn't do. Long and short of it is, it's an algaecide and sterilizing agent that can have some benefit for some plants though users have seen a few types (especially Val and thin walled plants) die from its abrupt use. But others report using it on Vals and sensitive plants after an acclimation period of low dosing. One of those subjects where some people love it, others loathe it, and some people even feel strongly enough to have heated debates about it. Where I come down on it is, I keep it on hand for a few algae issues and use it out of the aquarium (to clean hardscape, etc) more than inside these days. I won't use it on shrimp, which are mostly what I have in my own these days.
Nothing good happens fast in an ecosystem.