RO Membrane Output

[ScottT]

I bought an RO Bucket last year. The RB5 with one membrane processes 8 gallons an hour, leaving 4 gallons of concentrate.

I am adding a second membrane this year. This will allow me to process twice as much per hour.

My question: If I assume my starting sap is 2% sugar, by adding a second membrane will my end concentrate stay at 4% sugar, or will it increase because I'm running the new concentrate through a second membrane?

[littleTapper]

If your flow rate of concentrate and permeate is equal; the sugar % of your concentrate will still be 4%. You'll just get through the sap faster.

If you change your ratio of permeate:concentrate, you can get higher sugar % of your concentrate. Overall processing rate will probably decrease some. RO Bucket does not suggest more than 50:50. There is risk of fouling membranes. I run my RB25 kit (since upgraded with higher capacity membranes plus another one) to at least 2/3 permeate, 1/3 concentrate, sometimes 75:25. I typically output 7.x% concentrate in one pass at a decent overall processing rate. Sap is normally just under 2% for me.

[ScottT]

Thanks. That's what I needed to know. I appreciate the help.

[littleTapper]

Thanks. That's what I needed to know. I appreciate the help.

You bet! You'll be finding yourself wanting to tweak and push your RO. Just have fun and have a great season!