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InADream
08/15/2007, 05:59 PM
I just got a reverse osmosis machine from a friend... I replaced the 6 month filters and the TDS meter still reads 245... Does that mean the membrane is bad, he said it was only 6 onths old... Does it need to be flushed or what....

Dream
Entropy
08/15/2007, 08:09 PM
It certainly sounds like it is bad. Was it left dry for a while perhaps? The only other thing I can think of is that the hoses are hooked up wrong or something. What is the TDS out of the tap?
SlowCobra
08/15/2007, 09:06 PM
Or the membrane actually isnt seated all the way after bouncing around in a car.
InADream
08/15/2007, 09:07 PM
I just found that the valve i had it hooked up to is low on pressure like 25 psi... I am hoping that it is only that reason and not a bad membrane... As far as i know it was only drained to ship it and not dry when i got it... he said it was working great but never had a meter..

Dream
Entropy
08/15/2007, 09:10 PM
25 psi is not going to cut it, but I still think 245 ppm is really high. How high is you tap?
InADream
08/16/2007, 03:08 PM
my tap water comes in at 195 and leaves at 245, I am going to get the pressure up and try and get a new readig from it... Anyone know where to get filmtec membranes cheap..

Dream
pogodzib
08/16/2007, 03:35 PM
Are you sure you didn't switch the waste water and RO water lines? At a waste water/good water ratio of 4:1, assuming your carbon filters aren't removing any TDS, incoming tap water of 195 will go out at 244 if your good water is going out at 0 TDS

Waste water @ 244 TDS * 4 gal + Purified water @ 0 TDS*1 gal = Incoming water @ 195 TDS * 5 gal
AZDesertRat
08/16/2007, 06:42 PM
Tell us what brand and model it is, is it an RO only or a RO/DI? Where are you testing from and what are you testing with?
Are you using a clean container to capture the samples in? Do you triple rinse it and the meter with DI or distilled water between tests?
If its an RO/DI what is your tap water TDS, RO only TDS without DI and finally RO/DI TDS?
What is the incoming pressure and water temperature?
If its a RO/DI how old is the DI cartridge?
What is the waste ratio, as in how much waste do you get in relation to the good water?
What colors are the tubing, and what color are you testing from?