Get a drop checker, its a useful tool for a high tech planted tank.
The gist of a drop checker is that it changes color when there is more co2 in the water, you want it to be a nice green, maybe even pushing yellow if your fish don't act funky (fish gradually adjust to higher co2 levels) as this indicates ~30ppm co2 in your water.
The more light, the faster co2 is taken out of the water by plants, so you're going to have to adjust your co2 output with the needle valve on the regulator so that when the lights are on the drop checker is consistently at least a green color. But if your fish are behaving strangely with the co2 or stick to the very surface of the tank because of it you have to dial it down.
Even with co2 injection you still need good flow in your tank and surface rippling to allow for increased oxygen absorption into the water. But don't break the waters surface as that gasses of co2 more than you'd want in this setup.
Also, this is assuming you are using a co2 regulator, I wouldn't want to do high light with a DIY co2 setup. If you are running medium or low light (think no more than 35PAR) you are generally fine without running any co2. But if you're hitting big PAR numbers (50 is high....if you're really knowing what you're doing with lighting and co2 and planted tanks I've seen people run PAR levels of like 130+) you NEED TO BE ON YOUR CO2 GAME (unless you are an algae farmer in which case good job you're going to grow all the algae you'll ever desire with that kinda light).