Reverse osmosis

Four calculators for your RO: what it is doing, and whether it is doing it well.

Concentrate Brix#

The Brix you end at after taking a given amount of water off. It works both ways:

• Find my Brix: type the Brix going in and your concentrate and permeate flows, and it gives the concentrate Brix and the water removed.
• Hit a target Brix: type the Brix you want to end at and your permeate flow, and it tells you what to set the concentrate flow to.

Flows are gallons a minute, the way most RO gauges read. Brix going in can be raw sap or concentrate you are running a second time.

What a batch leaves you#

How much concentrate and permeate you end with, and the syrup that makes. Type the raw sap, its Brix, and the Brix you concentrate to.

The syrup at the end is the same either way, because RO removes water, not sugar. What changes is how much you no longer have to boil off.

Is my membrane healthy?#

How much sugar the membrane keeps. Type the Brix of the raw sap and the Brix of your permeate.

Rejection needs the permeate reading, not the concentrate. Under 99 percent retained, the permeate line is carrying money away. Below it, the concentration ratio: how many times over you concentrated.

Membrane flux#

What your membrane is doing against its rating. Type the sap temperature.

Water pushes through a warm membrane more easily than a cold one, about 3 percent per °F, and machines are rated at 77 °F. Cold sap is not a fault; it is why the first run of the morning crawls.

FAQs