Quote:
Originally Posted by PhreeBYrd
So you have replaced the membrane? When? How old is your current membrane?
For your output TDS to be the same as your tap water, the water must be completely bypassing your membrane (or blowing right through it), although the way membranes are made and normally plumbed, I'm having a hard time visualizing how that could even happen.
Are you sure there are not valves open (or closed) somewhere that cause the water to bypass the RO membrane? Who is the manufacturer of the original RO/DI system?
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LOL. Yes. I haven't been using the same RO membrane for 12 years. I've changed it quite a few times, most recently being this past June. The only difference is that before I had always used Filmtec TW30-1812-75. Now they want me to use BW60-1812-75. For all intents and purposes it's the same membrane dimensional-wise, but with a new type of membrane with a higher salt rejection. Almost every vendor that sells reef products/water purification products sells this membrane to go into a standard RO housing. That's what I have - a standard RO housing. There's nothing strange or unusual about it. The membrane slips right in and fits like glove.
There are no other valves or bypasses installed on the system. It is a generic unit. The water is just simply not being forced through the membrane properly.
In the meantime I've purchased a new housing and restrictor (550ml). A small investment for replacing 12 year old components. The housing arrived and was almost exactly the same as the one I received 12 years ago. Same with the restrictor. Once hooked up, same results - barely any water from the waste line. A bit more through the clean water line, but still the same TDS as tap.
My conclusion at this point is that I have a defective membrane. As strange as it sounds, I have to only assume that even Dow lets a bad one get through from time to time. There is simply no other thing it can be. Unless my original ro housing went "bad" somehow and the new one I replaced it with is "bad" in the exact same way. It has to be the membrane. The good thing is that this model of membrane tends to be half the price as the original one. Since I'm long past the return period, I'll just have to swallow the loss and move on.
I'm going to try and locate the original TW30-1812-75, but I couldn't find it before. I'm just hesitant going with the same model again after having this problem.