Needle valve?

[Ma98tron]

Do you need a needle valve on your concentrate line for back pressure, if so how do you know how much to close it?

[metalhead62]

restriction on the concentrate side is what forces the sap through the membrane in most ro's there are flow meters and pressure gauges that tell you what to set it at to get what you want ie less flow on the concentrate side means higher sugar content in the concentrate but at the cost of less overall water removal i assume u were looking at the tread i started earlier and i was talking about a cobbled up system beause i lack the money and time to buy the rest of the parts you would not want to run a high pressure pump without gauges and and meters for safety and the likeliness of messing up other valuable components but with the lower pressure i was talking about the risk are negligible