So this is what the plant company in California had to say when I asked about red plants as easy to grow as Java & Anubias. I have absolutely no idea how CO2 is used to support the plants.
That is much what I said initially. "Growth light" means sufficient light intensity to drive photosynthesis, more needed for red plants, and ensuring the necessary nutrients are adequate. Liebig's "Law of Minimum" is that plant growth will be full out until some factor is no longer sufficient, then it slows and may even stop. Light is one such factor, as is every one of 17 nutrients that must be sufficient to balance the light.