Same direction as when concentrating. Start with as close as you can to 50/50. Then as the membranes get cleaned, you adjust the pressure to try to stay at 50/50. Check you membrane manufacturer to know the max temperature. Mine are 113F, others are different.
I start at 110-113, but then I send the permeate component thru my tankless water heater before it returns to the wash tank since it cools very quickly until the membrane canister contents get up to temperature. Once back up to 110-113 it might not need further heating.
No reverse flow wash or rinse.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.