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Old 10/06/2007, 11:19 AM   #1
383camaro
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new ro membrane slow water production?

I purchased a 100gpd ro unit from filter direct abt 3 yrs ago. It recently started creating a LOT of waste water and the production slowed down a little bit. The TDS was still low. I decided to change the membrane when I changed my prefilters. I purchased a kent marine hi-s 60gpd membrane and the restrictor from marine depot. The restrictor was listed as 50-60 gpd. Since I did the change, my TDS is now 25ppm after the ro unit and production is way down. A 7 gal jug used to take me 2 hrs 20 mins and now it takes 7 1/2 hrs. I have 65 psi water pressure during production after my prefilters. I removed what I believed to be the restrictor for the 100gpd membrane (a piece of plastic abt 2 1/2 in long that read 550 on the outside) and I placed the restrictor in the waste water hose (w/c was where the old restrictor was) .
My question is, do new membranes take a while to break in? I've made approx 100 gal of water so far. What is normal TDS for an RO unit? My old TFC membrane was FAR lower with a reading of 5. Did I install the flow restrictor in the right spot (with the little black hose downstream)?
Thank for any help that you can give me.


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Old 10/06/2007, 01:27 PM   #2
AZDesertRat
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No they do not take long to break in. I assume the Kent came with a capillary tube type flow restrictor? Have you timed your good and waster flows to ensure you are at a 4:1 waste ratio? Higher waste flows reduce product or good water flows. I really like the capillary tube restrictors as they can be trimmed to exactly fit my pressuer and temperature where the other larger one is no nadjustable so you get what you get.


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Old 10/06/2007, 06:11 PM   #3
383camaro
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Is 25 tds normal for this membrane? Will trimming the restrictor tube increase production of good water or waste water?How do you Know when to change the membrane?Was mine bad or did I just need a new flow restrictor?
Thanks again.


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Old 10/06/2007, 06:55 PM   #4
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RO TDS depends on your tap water TDS and how well the membrane is working. What is your tap TDS? 25 sounds high since the Kent is supposed to be a premium type membrane.
I use a Spectrpure Select series hand tested membrane. my tap water TDS is 835, my RO only runs between 5.3 and 6.2 and my RO/DI is a true 0 TDS or about 18.2 megaohm resistivity.
Triming the tube would increase the waste production so you may have the wrong restrictor to begin with. You might not have the membrane seated all the way in the housing either which could be the reason for the increased TDS.


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Old 10/06/2007, 07:02 PM   #5
marcsmith73
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An R0 unit will run usually between 13-25 PPM. With DI zero...

On the other hand. What is your PSI at? You will need to push 40 PSI, and above to penetrate the membrane. Maybe there is a clog somewhere? It is 3 years old...


Thanks my friend.

~Marc


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Old 10/06/2007, 07:47 PM   #6
383camaro
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Thanks guys, my tap water tds is 675. I thought that was really bad... don't drink that stuff. I'll try removing the membrane and reinstalling it. The restrictor is listed for 50-60 gpd. If it were better sized for a 50 gpd what would that do on a 60 gpd unit?as far as flow and tds. Could my new membrane be defective?

Thanks again.


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Old 10/06/2007, 08:22 PM   #7
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holy smokes!!! 675?


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