Eating Up RO Membranes

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flyfisher2

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Hello Reefers,
I need some help. I've been eating up RO membranes for over a year. I'm on my 4th. All brand new, all Dow Filmtec. I flushed the sediment, carbon filters prior to hooking up to the RO membrane. All was working well had a rejection rate 0f 5 prior to DI. I produce about 60 gallons a week and all was good for the last three months. Last week it creeped up to 3 TDS then 7 this week. I disconnected the hose between the membrane and the DI and tested the water from the membrane. The reading is 108. Waste water shows 256. I changed the DI and I'm getting 0 TDS DI but I already know the DI will be exhausted in no time. As I said this will be the 4th Membrane since April of last year. Please tell me what can be causing this. What I'm doing wrong?
 
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flyfisher2

flyfisher2

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I need to stop replacing these as often as the sediment filters
 
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KStatefan

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"I disconnected the hose between the membrane and the DI and tested the water from the membrane. The reading is 108. Waste water shows 256"

How much water had you run thru before taking this reading? If is was when if first started up it could be TDS creep
 
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CMMorgan

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You on well water?
NO hot or warm water is being used is it?
What does hot or warm water do? We are in Florida - our water is always warm - hot in the summer. (Pipes are in the attic) great for showers...
 
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Woodyman

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What does hot or warm water do? We are in Florida - our water is always warm - hot in the summer. (Pipes are in the attic) great for showers...
Hot water degrades filters and if hot enough can actually melt the film of the RO membrane.
 

Mike konesky

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What does hot or warm water do? We are in Florida - our water is always warm - hot in the summer. (Pipes are in the attic) great for showers...
Hot water can burn up your membrane and system. If your outside line is exposed to the sun then it may be a good idea to flush the feed line until it's tap temp.
 

Woodyman

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Have you tested for chlorine/chloramines post sediment and carbon? If not just based off of what I've read so far I would start with that and diagnose based on that result.
If your chlorine/chloramines are high enough you could be burning through carbon quicker than your changing which is leading to the premature death of your membranes.
 

CMMorgan

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Hot water degrades filters and if hot enough can actually melt the film of the RO membrane.

Hot water can burn up your membrane and system. If your outside line is exposed to the sun then it may be a good idea to flush the feed line until it's tap temp.
Good information. My RODI does an automatic flush but not long enough to get to cool water. I will try running a faucet in the same line prior to starting to fill the ATO reservoir. Appreciate the advise.
Sorry, OP, but I cannot think of anything else that you have not tried. Perhaps try ordering the membrane from another supplier? Is there a chance that the ones they sell you are just old? Also consider getting your water tested independently.
 
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