You can't tell how much CO2 you have by measuring the pH and KH of the tank water. You can use a drop checker, with 4 dKH water, made from distilled water with nothing but baking soda in it to reise the KH to 4 dKH. Even that will only let you estimate the ppm of CO2 to be within the range of about 15 to about 45 ppm. Accurately measuring ppm of CO2 is very hard to do without spending a lot of money for professional equipment.
If your fish are not gasping for air at the water surface you probably have less than 40 ppm of CO2, but that could be 10 ppm on up. If you want to go higher in CO2 you need to be sure you have good oxygenation of the water, by having the whole water surface well rippled, as a start, and you need very good water circulation in the tank so the CO2 is available to all of the plants, plus you will need good maintenance habits, to keep the tank, filter, and water very clean.
How much light you now have depends on whether those bulbs have good reflectors, no reflectors, or something in between, and it depends on having a ballast that drives the bulbs to their rated power. Then it depends on how high above the substrate the light is.