I did a flush for the first time about 2 weeks ago, let the system run like an hour before adding nutes.
2 buckets, 2 gallons water each, hydroton, water for 15 minutes every hour, cut water way back when lights are off. Temps are between 70-85 had powdery mildew and just got it under control.

Last 3 weeks PH drops from over 6.0 to mid 5 in 24 hours. Last 4 days since using baking soda to up PH. Problems going high for 2 days, now for 2 days PH has not moved from 6.3 and I double check it.

PPM can go up but never in both buckets just 1.