RODI FILTER ISSUE

Ecotech Marine

ggNoRe

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I purchased a 6 stage 100GPD RODI unit from purewaterclub.com. Everything was going well for about the first 400 gallons (I have a 200G system) and then TDS started to creep up. I changed the 2 DI filters and it went back to 0. After about only 20-60 gallons later TDS started to creep up again. This time I changed the first 3 sediment filters. That didn't help at all. So I changed both DI filters again. This brought me back to 0 TDS but only for about 20 gallons this time. I tested my tap water and it reads 285 tds. I tested the water after passing the RO stages and it reads 185. The only filter I haven't changed at this point is the RO membrane. Question is should I bother changing it and both DI filters again or just scrap it and buy a 7 stage BRS RODI system?

Also worth noting is I did a ICP test and it read about 750ug/L silicone and I am battling dynoflagelletes.

Any input is greatly appreciated.
 
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I would look into checking your co2 levels in the water, this can lead to burning through di resin. Also are you running unit at proper psi? I like to run mine between 70-80 psi. Does the unit have a flush valve?
 

Gtinnel

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If your home has good water pressure then it probably has enough for the filter, although it is good to know, and as far as I know most people who have CO2 issues are on well water. With the tds after the membrane being that high I wonder if it is an issue with one of the seals on the membrane allowing water to bypass the membrane completely. If I were you I would re-seat the membrane and check the seals.
 
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ggNoRe

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Today I took apart every stage inspected them made sure they sealed properly and put the system back together. Ran 10 gallons after about 5 gallons it bottomed out around 27 TDS and then started rising again up to 37. Think I'm about ready to throw in the towel with this filter and just spend $350 on the 7 stage BRS one. :(

Sent 2 emails over the past 3-4 days to manafacturer, no response.
 

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If you’re gonna replace the membrane, replace it with a Dow Filmtec 75 GPD membrane and the correct corresponding flow restrictor (BRS recommends 550 ml/min for a 75 GPD membrane). The 75 GPD Dow membrane has the best rejection rate.


 
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When you say you got a 6 stage system from Pure Water Club, I assume you got something like this?

3BB31095-E1D3-4376-B9A8-426B0FDEDF9B.jpeg

If so, and after you verify that the RO membrane change worked to lower your post RO water to within spec, I would get rid of the two horizontal cylinders after the RO membrane and replace it with a proper vertical DI set up. Something like this...


These changes will essentially turn you system into a BRS 7 stage unit.
 

NatureHold

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Did you flush the whole system, particularly the RO membrane before you started making tank water? Most RO membranes have a preservative coating on them that will kill your DI resin super fast if you don't flush about 30 gallons or so through it.
 
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ggNoRe

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If you’re gonna replace the membrane, replace it with a Dow Filmtec 75 GPD membrane and the correct corresponding flow restrictor (BRS recommends 550 ml/min for a 75 GPD membrane). The 75 GPD Dow membrane has the best rejection rate.


Doh! Unfortunately, one day too late. I just purchased the membrane from the same company. For some reason the 6 stage unit I purchased from them is no longer on their website for sale.

It is 2 carbon filters, a sediment filter, 100GPD membrane, and 2 DI filters.
 

Water Dog

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Doh! Unfortunately, one day too late. I just purchased the membrane from the same company. For some reason the 6 stage unit I purchased from them is no longer on their website for sale.

It is 2 carbon filters, a sediment filter, 100GPD membrane, and 2 DI filters.

Is the layout similar to what I posted above?
 
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Opus

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Doh! Unfortunately, one day too late. I just purchased the membrane from the same company. For some reason the 6 stage unit I purchased from them is no longer on their website for sale.

It is 2 carbon filters, a sediment filter, 100GPD membrane, and 2 DI filters.
Hopefully your current RO membrane just has a bad seal and not that the membranes they sell are junk. A good membrane should be getting you 98% rejection rate so you should be seeing a tds of around 6 before the DI. FYI, the sediment and carbon filters do nothing for tds really, their only purpose is to protect the RO membrane. Also, if you don't let any chlorine get to the membrane, it should last 5+ years unless you are making a ton of water.
 
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ggNoRe

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Hopefully your current RO membrane just has a bad seal and not that the membranes they sell are junk. A good membrane should be getting you 98% rejection rate so you should be seeing a tds of around 6 before the DI. FYI, the sediment and carbon filters do nothing for tds really, their only purpose is to protect the RO membrane. Also, if you don't let any chlorine get to the membrane, it should last 5+ years unless you are making a ton of water.
That order is correct Water Dog.

Opus, unfortunately I only used it for about 6 months. The seal looked good when I checked. I gave the wrong reading earlier. I took the TDS from the tube going to the membrane. After I re-sealed everything I checked again from the proper output coming from the membrane and the TDS was 35. My tap water is 255. After DI at that time was 25 TDS.
 
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ggNoRe

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After replacing the membrane I was down to 4TDS with 14TDS coming out of RO before DI. So I changed the DI filters which I only replaced like one week ago again. That did get me down to 0 TDS.

Looks like you get what you pay for and this is what happens when you go with a RODI that's priced less than half of what similar ones are. The filters are crap and constantly need replacing. Already spent the same amount from buying filters as I would have if I had just bought a proper RODI in the first place.
 
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