Agree, discus or not water change should be done.
Once per week or month. I do 80% weekly for the first 3 month.
After that I do 50% per 2 week.
Some guy do 10 water change in 6 yr using a sump/ refugium
Yet in a natural, dirted, planted tank the water parameters are golden for much longer than that. It comes down to fish load. I know a guy who is stocked so heavy that he does several water changes a week, another who goes maybe 5 months and his fish and tanks are gorgeous. Not discus mind you - discus are their own ball of wax.