Hi all. I have had a BRS 4 stage RODI unit for almost 2 years now. Recently i replaced all the filters as part of the routine maintenance (sediment,carbon,DI). However once i turned the system on and let it run for several minutes, I noticed my tds coming out of the RO membrane (before it goes into the di) was around 8-12 TDS. Normally this is around 3-4 TDS before I changed the filters. My pressure is around 85 PSI like usual (I use a booster pump) Also i noticed my water production has dropped by about HALF of what it usually is. Instead of 1 gallon every 15 minutes, i get 1/2 gallon. Why would replacing the filters do this? Im so confused..
Werid BRS RODI Unit Issue
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Fudsey
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Did you flush your membrane when you ran it the 1st time for a while?
Fudsey
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It could also get clogged with dust from the carbon filter as well 
No I did not replace the membrane. It's the original membrane that came with it and it's almost 2 years old. Cant imagine I already need a new membrane. All I did was replace sediment, carbon, and DI resin.
Good point. But if that's the case I'm curious why BRS mentions nothing of this in their videos and instructions. Or how to prevent this from happening.It could also get clogged with dust from the carbon filter as well
Brett S
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I have two thoughts on this... first, as far as the higher TDS from the membrane goes, when the RO membrane sits idle it’s possible for things that would normally be rejected to make it across the membrane. Because of this, when you first turn on the RODI you will normally see high TDS coming out of the RO membrane before the DI resin. This is usually referred to as ‘TDS creep’ and it will resolve itself after water has been running though the filter for 5 or 10 minutes.
If you saw the high TDS reading shortly after you started the RODI then I suspect this might be what you are seeing. Let it run for another 20 or 30 minutes and see if it comes back down to normal.
As far as the low output rate I’m wondering if your new prefilter might be different that your old one... for example you might have switched from a 5 micron filter to a 1 micron filter. The 1 micron filter will be more restrictive and might reduce your output (although it seems a bit surprising that it would cut it in half).
It’s also conceivable that one of the new filters is bad.
If you still have the old filters it might be worth putting them back in one at a time to see if you can narrow down the flow issue to one filter.
If you saw the high TDS reading shortly after you started the RODI then I suspect this might be what you are seeing. Let it run for another 20 or 30 minutes and see if it comes back down to normal.
As far as the low output rate I’m wondering if your new prefilter might be different that your old one... for example you might have switched from a 5 micron filter to a 1 micron filter. The 1 micron filter will be more restrictive and might reduce your output (although it seems a bit surprising that it would cut it in half).
It’s also conceivable that one of the new filters is bad.
If you still have the old filters it might be worth putting them back in one at a time to see if you can narrow down the flow issue to one filter.
