I agree with Byron, I would not use pH adjusting formula's.
Discus will be fine with the pH so long as it is stable.
I would monitor the water for Ammonia,nitrites,and be prepared for any rise in those number's = immediate water change.
Ammonia and nitrites must read zero for fish to remain healthy and nitrates are best kept under 40 ppm as per test kit result's with 20 ppm or less being ideal.
Would remove any uneaten food after one hour via gravel vaccum and feed less if uneaten food becomes problem.