No. There is more here than just CO2.
First, I would not add pure ammonia to a tank (as in the cycling) with live plants. Ammonia is highly toxic to all life, including plants, not just fish. While it is true that plants can take up a lot of it, there is a limit, and you may have exceeded it. I'll come back to this.
Second, your required plant nutrients of which there are 17 are likely not all present, since you are not adding any liquid fertilizer. A tank full of fish that are being fed might provide sufficient trace minerals and such for plants, but this is not likely to occur in a new set-up. A good complete liquid fertilizer such as Seachem's Flourish Comprehensive Supplement or Brightwell Aquatics' FlorinMulti should be added at the dose recommended on the label, and once a week.
Another nutrient issue concerns the "hard" minerals. What is the GH of your tap water? Don't need to test this yourself, you can find out from the water folks. The hard minerals in prepared fertilizers can be insufficient if the source water is very soft (like mine is), so it is good to know the GH. Yours may be fine, but it is another thing to check.
On the CO2, this occurs not only from respiration of fish, plants and bacteria but primarily from the breakdown of organics in the substrate. Obviously in a new tasnk this is going to be minimal. But I have never had plant issues in new tanks from CO2, just slower response until the organics build a bit. The other nutrients are more critical at this beginning stage. The enriched substrate is not likely to provide all of them; to begin with, some nutrients are taken up primarily through the leaves of aquatic plants, not the roots. Also, I do not know just what minerals are in the mentioned substrate. I have used others like Flourite and Eco-Complete, and found that liquid fertilizer was still essential.
Now, back to the ammonia item. Plants need nitrogen, and they prefer it as ammonium. The ammonia produced by fish and the breakdown of organics is readily taken up by live plants and changed into ammonium (in acidic water ammonia automatically changes to ammonium which is basically harmless). I personally would not add ammonia to a new tank if live plants are in there. Get some fast growing types, like floating plants which are ideal for this as they can readily assimilate atmospheric CO2 so they can grow fast in new tanks. If you do, then you can add those little fish with no worries. But do some major water changes to get rid of the artificial ammonia.
Last a general comment on Sagittaria. I find this a somewhat slow growing plant, compared to the very similar chain and pygmy chain swords for example. But it should not be melting apart as in the photo.
Byron.
