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?