Cleaning membranes

[Beerclouds]

I have 3 400 gpd membranes that need a cleaning..i read i need to use 200 gallons per nembrane to flush..really????

[maple flats]

I'd be very surprised. Normally an RO is rated in gal/hour. If a 400 gpd is translated to gal/hr, divide by 24. That rounded gives you 17 gal/hr. That is about what you need to clean it. Start with a cold permeate rinse, to push sweet to your concentrate tank. Let it flow for about 4-5 minutes, control the pressure so both permeate and concentrate hoses appear equal flow. Then add about 1 gal of hot permeate (about 100F) in a wash bucket, Add the soap recommended by the membrane manufacturer, usually a lye solution, in your case maybe a teaspoonful. Run that for 10 minutes with both hoses returning to the wash "tank". Then rinse, using cold permeate for 5 minutes. If you need an acid wash, after the above is done, set another bucket with 1 gal cold permeate, add a teaspoonful of "reaLemon" or similar lemon concentrate. circulate for 5 minutes, rinse with cold permeate for 5 minutes. Then do another soap wash as before and finish with at least 5 minutes rinse. In all of that, you will have most likely used between 15 and 20 gal of permeate. If this was after the end of the season, let it set for a week with the lemon wash to dissolve any mineral trapped in the membrane(s). Then do a soap wash, cold rinse and put it away for the next season.
The soap wash removes organic fouling, the acid wash removes mineral debris in the membrane.

[ecolbeck]

I have essentially the same setup and I flush with 10 gallons permeate after each use.

[Beerclouds]

thank you so much dave...this is so helpful