Flow restrictor for RODI System

yman182 · Dec 9, 2020

Hello All,

I am using a Spectrapure 90GPD Membrane

SpectraPure® SpectraSelect Plus 99% Rejection RO Membrane 90GPD - MEM-

SpectraPure‚ SpectraSelect‚ Plus¢„¢ 99% Rejection Membranes set the industry standards for contaminate removal, high flow rate, and membrane longevity! Manufactured in the US, Hand Tested for Quality! Trust SpectraPure‚ for all of your RO & RO/DI needs

spectrapure.com

and am about to replace my autoflush valve as mine seems to be defective. Does anyone know what the proper size for the filter I have is so I can purchase the proper new one?

Spectrapure mentions that I need to size it properly, but never says what the size is!

Auto Flush Flow Restrictor

Choose the Aquatec Auto Flush Flow Retrictor that meets your RODI systems flow rate. 300 mL/min 400 mL/min 500 mL/min for 75 GPD single membranes or 150 GPD Water Saver Systems 800 mL/min for 100 & 150 GPD single membranes or 200 GPD Water Saver Systems The Aquatec Auto-Flush Flow Restrictor...

www.bulkreefsupply.com

I know that BRS gives recommendations at the bottom, but I am not sure if those will work for the spectrapure RO membrane. I think they are just a 75GPD membrane that is rated 90GPD at a higher pressure.

Any help would be appreciated!

Reef. · Dec 9, 2020

You match your membrane, it’s just to make sure the amount of pressure going to the membrane does not over power it.

yman182 · Dec 9, 2020

Reef. said:
You match your membrane, it’s just to make sure the amount of pressure going to the membrane does not over power it.

What does that mean exactly? If my membrane is rated at 90GPD at 60PSI, how many ml/min flow restrictor do I need?

Reefnman2 · Dec 9, 2020

I see what you mean, I would go with the 600 or 700 ml for 90gpd.

yman182 · Dec 9, 2020

Reefnman2 said:
I see what you mean, I would go with the 600 or 700 ml for 90gpd.

Awesome thank you. Can I ask how you came to that number? I am very curious about how all this stuff works!

Reef. · Dec 9, 2020

yman182 said:
Awesome thank you. Can I ask how you came to that number? I am very curious about how all this stuff works!

If you get no joy here I would open a live chat with BRS and ask their advice as the way I worked it out was 90g\24hours which gives 3.75 gallons you are making an hour, convert that to ml, gives 14,193ml then divided by 60 mins, which then gives 236.5ml so I would guess if my maths is right the 300ml would be the one but going by BRS’s recommendations they seem to recommend higher rated flow restrictors?

Water Dog · Dec 9, 2020

Spectrapure 90 GPD membranes are rebranded Dow Filmtec 75 GPD membranes. They used to be batch tested to get the 99% ratings though I’m not sure that is done anymore. They get the 90 GPD rating from the higher 60 PSI pressure recommendaction. Push water at 50 PSI through it and you’ll get 75 GPD.

theMeat · Dec 9, 2020

yman182 said:
Hello All,

I am using a Spectrapure 90GPD Membrane

SpectraPure® SpectraSelect Plus 99% Rejection RO Membrane 90GPD - MEM-

SpectraPure‚ SpectraSelect‚ Plus¢„¢ 99% Rejection Membranes set the industry standards for contaminate removal, high flow rate, and membrane longevity! Manufactured in the US, Hand Tested for Quality! Trust SpectraPure‚ for all of your RO & RO/DI needs

spectrapure.com

and am about to replace my autoflush valve as mine seems to be defective. Does anyone know what the proper size for the filter I have is so I can purchase the proper new one?

Spectrapure mentions that I need to size it properly, but never says what the size is!

Auto Flush Flow Restrictor

Choose the Aquatec Auto Flush Flow Retrictor that meets your RODI systems flow rate. 300 mL/min 400 mL/min 500 mL/min for 75 GPD single membranes or 150 GPD Water Saver Systems 800 mL/min for 100 & 150 GPD single membranes or 200 GPD Water Saver Systems The Aquatec Auto-Flush Flow Restrictor...

www.bulkreefsupply.com

I know that BRS gives recommendations at the bottom, but I am not sure if those will work for the spectrapure RO membrane. I think they are just a 75GPD membrane that is rated 90GPD at a higher pressure.

Any help would be appreciated!

Do you have a spectrapur unit , or just membrane?
Either way you could use a spectrapur flow restrictor, which is internal, and can be adjusted for your water pressure.
If not, 700 a good bet

yman182 · Dec 9, 2020

theMeat said:
Do you have a spectrapur unit , or just membrane?
Either way you could use a spectrapur flow restrictor, which is internal, and can be adjusted for your water pressure.
If not, 700 a good bet

I am not using a spectrapure system, just the membrane. I want to use one of the auto flush restrictors which is why I can’t use a capillary type.

theMeat · Dec 9, 2020

yman182 said:
I am not using a spectrapure system, just the membrane. I want to use one of the auto flush restrictors which is why I can’t use a capillary type.

Ahh
You want about 4 to 1 waste/product ratio. If much less waste to product your membrane will expire prematurely, if much more your pre membrane filters will expire needlessly.
Would try a 700 and measure/test your ratio and go smaller if needed.