Another RO/DI Issue - High TDS after RO Membrane

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warped_insanity

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I have a Waterbox 130.4 coming soon - I want to know this groups thoughts on my RO/DI water - I’m at a loss and can’t figure out what my problem is. I had posted a previous thread last week but now I have the booster pump installed and also installed a pressure gauge. When I first hooked the RO/DI up, I was burning through DI resin really fast so I checked the post RO TDS.

I’m on a 500ft well around Houston, Tx. Water coming directly from the well is 330 TDS and 73 degrees at the moment. I had pretty bad water pressure so I installed a Smart Buddie pump which boosted my pressure into the RO membrane to 85 psi. My RO output (pre DI) is at 20 TDS - below the 75gpd Dow rejection stats. I contacted BRS who thought I had a bad RO membrane, so they sent me a new one. I have the exact same TDS after installing the new membrane. And my product water vs. waste water is around 1:1 - the product water is actually producing a little more than the waste which shouldn't be the case. I'm certain the RO membrane is snug and installed correctly (I've re-set it a number of times) and I know my booster pump is also set up correctly.

RO housing possibly bad? Smart Buddie not restricting enough flow? I have no idea - I don't want to take advantage of BRS and keep asking for replacement parts.
 
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Gtinnel

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I was burning through DI resin really fast so I checked the post RO TDS.
I don't have well water but I know that it isn't uncommon for well water to have a substantial amount of CO2 which can quickly deplete your DI. I've even seen threads on here where other users have ran their well water through the membrane and then stored it in a container to off-gas before running it through their DI. I don't know if that is your issue or not but just wanted to mention it.
 
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warped_insanity

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You have the filters in the right containers? Di is last?
Call air water and ice tomorrow in flordia. My water ppl. See what they say. Tell em brs sent u a new membrane and u have same issue with the 20tds.
-d
Oh yes, checked many times for user error! I don't even have water going to the DI right now - just trying to figure out why my post RO TDS is so high!
 
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warped_insanity

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I don't have well water but I know that it isn't uncommon for well water to have a substantial amount of CO2 which can quickly deplete your DI. I've even seen threads on here where other users have ran their well water through the membrane and then stored it in a container to off-gas before running it through their DI. I don't know if that is your issue or not but just wanted to mention it.
I already have an off-gassing chamber ready for the CO2 if it is an issue - my main issue is why is my TDS after the RO membrane as high as it is (which also can cause DI depletion). 94% rejection rate currently.
 
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Gtinnel

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I already have an off-gassing chamber ready for the CO2 if it is an issue - my main issue is why is my TDS after the RO membrane as high as it is (which also can cause DI depletion). 94% rejection rate currently.

I'm not even sure if the CO2 raises tds. I've been reading online and some things said yes while others said no. Assuming CO2 doesn't effect tds, the only thing that I didn't see mentioned is if you have the correct sized flow restrictor? I believe the wrong size restrictor can mess with product to waste ratio and the rejection rate.
 

monkeyCmonkeyDo

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warped_insanity

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I'm not even sure if the CO2 raises tds. I've been reading online and some things said yes while others said no. Assuming CO2 doesn't effect tds, the only thing that I didn't see mentioned is if you have the correct sized flow restrictor? I believe the wrong size restrictor can mess with product to waste ratio and the rejection rate.
The Smart Buddie has you remove the flow restrictor since it supposedly takes care of that as well. I did try out re-introducing the flow restrictor just in case - same results.
 

Gtinnel

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The Smart Buddie has you remove the flow restrictor since it supposedly takes care of that as well. I did try out re-introducing the flow restrictor just in case - same results.
Sorry I'm not familiar with the smart buddie, although I did notice that you did mention restriction in your first post.
 
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Gtinnel

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330 - 20 = 310
265 / 310 = .854
.854 x 100 = 85.4 = % rejection rate

Either your water is super hard, or something is not right with your filters.
Not the it really matters but wouldn't his rejection rate be
330-20=310
310/330=.939
.939x100=93.9%

I still agree that 20ppm after the membrane is high, so I'm only asking because I thought it was the amount of tds removed divided by the incoming tds?
 
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I just replaced all the filters in my 7 stage and even added the chloramine monster hoping that might do something, even though I believe it just helps with DI resin. Its still at >20 pre DI. I have a soft water unit on my house, not sure if that makes an impact.
 
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