Welcome to the obsession. You should know that the amount of water you change can have a significant impact on the quality of your discus. Regardless of the amount of filtration, nitrates can only be removed with water changes.
I have a 110 gallon tank which is the same height as yours, but only 18" deep. Wiping down the tank, particularly the bottom, is a weekly task. But the fish look great in a tall set up.
Good luck, Willie