Once you start injecting CO2 into the tank, you have to consider adding fertilizers like phosphorus, nitrogen.... into the water column too. Those extra chemical may have a negative impact to your discus too. Something to keep in mind.
Don't get me wrong, I love high tech Plant tank and Discus as well. However putting them together is not going to be an easy task. Plant tank with 30 ppm of CO2 will need to have at least 30 ppm nitrate and 10ppm of phosphorus for the plant to grow nicely. Discus does not like to be in the water with 30 ppm of nitrate
My 210 gal discus tank