pure RO water for flush
1st plant: first run off was PPM 230, PH 6.2, second run off of 1st plant was PPM 190, PH 6.3
2nd plant: first run off PPM 230, PH 6.5, second run off of 2nd plant was PPM 150, PH 6.4
3rd plant: first run off PPM 260 PH 6.4, second run off PPM 210 PH 6.4
4th plant...