membrane qeustion

[GROWSZOAS]

About a year ago i upgraded from a 40 gpd to one of your rated 90 gpd membranes. Over the last year i have been going through di resin a lot faster than i should be. So i pulled the di off line and checked the tds coming from the ro and found the reason why, the tds out of the ro is 25-27.
I have always kept up on my prefilter changes, my pressure is good, and i have tried reseeding the membrane with no luck. Do you guys have ang suggestions?

[SpectraPure]

I have a few questions before any suggestions.

Did you change to a 90GPD flow restrictor when you changed the membrane?

What is the waste rate in ml/min and what is the product rate in ml/min?

What is the TDS of the Tap Water?

What is the pressure on the membrane?

Have you been using our DI resins? Which ones?


Scott
SpectraPure, Inc.

[GROWSZOAS]

First tanks for the quick response!
pressure is 45
tap tds is 212
i did replace the flow restrictor
im about 4/1 waste/product. I would have to go test to give you an accurate number
and i have been using a bulk di resin from my lfs

[GROWSZOAS]

did a test on the amount of water im making and its not like i thought.
waste rate 500ml per min
product rate 325 per min

[SpectraPure]

I'm sorry to say, I think you have ruined the membrane, with only a 1.53 to 1 ratio.

The FR needed to be adjusted (shortened) to get enough waste water to keep the membrane clean. Sounds like you assumed you had a 4:1 ratio, but didn't measure it to be sure.

See this Membrane Replacement Guide:

http://spectrapure.com/manuals/PRINTER_FRIENDLY/memRepGuide.pdf


We can sell you a new MEM-0090 for $35. It should give you about 8ppm RO water.

Scott
SpectraPure, Inc.

[GROWSZOAS]

Do i need to cut the flow restrictor?

[SpectraPure]

You can cut the flow restrictor by following the instructions in the manual noted above, but it won't fix the existing membrane. You will then need to adjust another new FR when you get a new membrane.

Scott
SpectraPure, Inc.

[GROWSZOAS]

thanks for all your help, should i pm you about the new membrane?

[SpectraPure]

Probably best to call our office (800-685-2783) on Friday and ask for the $35 deal on the 90 GPD membrane and get a $5 90 GPD flow restrictor.

Scott
SpectraPure, Inc.

[GROWSZOAS]

is that membrane equal to the one i have now?
it was the one of the rated ones?

[SpectraPure]

If you want a rated (hand-tested -- 98% instead of 96% rejection) one, they are $10 more and subject to delays as they don't test them every day.

Scott
SpectraPure, Inc.