New RODI with High TDS....Stumped

[TunnelRatt]

Well, now...that's interesting. So, inlet TDS, flow restrictor, and fluctuations in water supply pressure are all ruled out.

I have to admit....it's starting to look like a membrane or membrane housing issue.

I assume you've double-checked all the tubing to ensure it's been connected correctly?

I sent photos to BRS previously and they confirmed all looked okay?

What would be a housing issue? Out of shape / warped?

 

[AllSignsPointToFish]

I sent photos to BRS previously and they confirmed all looked okay?

What would be a housing issue? Out of shape / warped?

It would have to be something like that or a scored sealing surface to allow rejected water to contaminate the product water and cause high TDS.

I suppose you can pull the membranes and perform a visual inspection just to make sure there is no evidence of damage to the membrane, seal, or O-rings.

 

[Quietman]

I find it helpful to focus on the parameter that's the most out of whack in troubleshooting anything.

Can I ask where you're monitoring pressure? Inlet or after filter, after RO?

Also, when you measure pressure from tap can do you change system load (turn on a faucet, flush a toilet) see if pressure drops. If you have varying pressure under load that could impact RO performance.

Your TDS RO out should be no more than 5% of your input (187) and lower with new unit. So I'm thinking 10 max. 12 isn't too far outside but new unit should be more like 2%.

I have a fairly high variable input (tap) TDS from 300 up to 450 measured days/weeks apart. This mean i have high teens TDS out of RO into DI. 0 out of DI.

Is your TDS in (tap) steady?

 

[TunnelRatt]

It would have to be something like that or a scored sealing surface to allow rejected water to contaminate the product water and cause high TDS.

I suppose you can pull the membranes and perform a visual inspection just to make sure there is no evidence of damage to the membrane, seal, or O-rings.

I did look at them when I got the unit and I didn't see anything, but I'll check again to be sure. Guess, I'll have to get in touch with BRS.

I was thinking that I might pick up another membrane from another source to see if BRS received a bad batch of membranes. What's a good place to pick one up from? Would I need the 800ml flow restrictor in order to do so with only one membrane?

 

[TunnelRatt]

I find it helpful to focus on the parameter that's the most out of whack in troubleshooting anything.

Can I ask where you're monitoring pressure? Inlet or after filter, after RO?

Also, when you measure pressure from tap can do you change system load (turn on a faucet, flush a toilet) see if pressure drops. If you have varying pressure under load that could impact RO performance.

Your TDS RO out should be no more than 5% of your input (187) and lower with new unit. So I'm thinking 10 max. 12 isn't too far outside but new unit should be more like 2%.

I have a fairly high variable input (tap) TDS from 300 up to 450 measured days/weeks apart. This mean i have high teens TDS out of RO into DI. 0 out of DI.

Is your TDS in (tap) steady?

Pressure gauge is mounted between 2nd carbon filter and ro membranes

I did notice a slight jump one day when a toilet was flushed , but it went right back.

The reading of 12, was just once and then returned to high teens an hour later. The numbers get higher, lower, and then higher, lower and continues to do the same thing

The tds range seems to be 185 - 200 at the faucet

 

[Quietman]

Pressure gauge is mounted between 2nd carbon filter and ro membranes

I did notice a slight jump one day when a toilet was flushed , but it went right back.

The reading of 12, was just once and then returned to high teens an hour later. The numbers get higher, lower, and then higher, lower and continues to do the same thing

The tds range seems to be 185 - 200 at the faucet

I'd be tempted to get a booster pump to stabilize and increase pressure up to optimal. RO membranes to work much better at higher pressures. Or before spending that, maybe someone you know on different city or closer to city pumps would let you run a test.

 

[AllSignsPointToFish]

I did look at them when I got the unit and I didn't see anything, but I'll check again to be sure. Guess, I'll have to get in touch with BRS.

I was thinking that I might pick up another membrane from another source to see if BRS received a bad batch of membranes. What's a good place to pick one up from? Would I need the 800ml flow restrictor in order to do so with only one membrane?

You can get a Dow high rejection membrane off of Amazon. Is it a 75GPD system or larger?

 

[TunnelRatt]

I'd be tempted to get a booster pump to stabilize and increase pressure up to optimal. RO membranes to work much better at higher pressures. Or before spending that, maybe someone you know on different city or closer to city pumps would let you run a test.

I did run it only using a single membrane at 64 psi with no difference. Isn't 64 psi adequate when running a single membrane?

 

[TunnelRatt]

You can get a Dow high rejection membrane off of Amazon. Is it a 75GPD system or larger?

The system is a 150gpd that consist of two Dow 75gpd membranes. I'll check Amazon...thank you.

Also, will I get the proper results running one membrane with the 550ml restrictor or will I need an 800ml to do so?

 

[AllSignsPointToFish]

The system is a 150gpd that consist of two Dow 75gpd membranes. I'll check Amazon...thank you.

Also, will I get the proper results running one membrane with the 550ml restrictor or will I need an 800ml to do so?

I'm surprised the 150gpd unit only has a 550 restrictor. Usually they install an 800 on systems with that capacity.

 

[AllSignsPointToFish]

Their website says you need a 550 for the 150gpd water saver version (which I assume you have). That makes sense since the waste to product ratio is 1.5:1 instead of the normal 3:1.

 

[jjstecchino]

The kicker is that you are producing more "RO" water than waste water. This points to a defective seal or cracked membrane. Make sure the membrane is completely seated and pushed into the housing. Also check the big seal around the membrane that is fitting snug and is not bent or torn. Or it could be that BRS got a bad batch of membranes, just so unlikely.

From what you describe it looks like a good bit of unfiltered water is getting into your RO water for some reason. The ratio of Waste/RO water should be around 3:1 for a single 75gpd membrane not 1:1 as you are getting.

 

[TunnelRatt]

The kicker is that you are producing more "RO" water than waste water. This points to a defective seal or cracked membrane. Make sure the membrane is completely seated and pushed into the housing. Also check the big seal around the membrane that is fitting snug and is not bent or torn. Or it could be that BRS got a bad batch of membranes, just so unlikely.

From what you describe it looks like a good bit of unfiltered water is getting into your RO water for some reason. The ratio of Waste/RO water should be around 3:1 for a single 75gpd membrane not 1:1 as you are getting.

I'm going to open the membrane housings and check again tomorrow. Thanks

 

[TunnelRatt]

Their website says you need a 550 for the 150gpd water saver version (which I assume you have). That makes sense since the waste to product ratio is 1.5:1 instead of the normal 3:1.

Yes, it is what I currently have.

 

[AllSignsPointToFish]

Yes, it is what I currently have.

So it seems that the restrictor is correct and functioning properly.

 

[TunnelRatt]

So it seems that the restrictor is correct and functioning properly.

It appears to be working properly. I got a measurement of 18 ounces in one minute...the online conversion chart states 550ml is 18.5977 ounces. I don't believe the difference would be an issue.

 

[AllSignsPointToFish]

It appears to be working properly. I got a measurement of 18 ounces in one minute...the online conversion chart states 550ml is 18.5977 ounces. I don't believe the difference would be an issue.

I agree with you. I was merely stating that the restrictor has been ruled out as a source of the problem.

 

[TunnelRatt]

The kicker is that you are producing more "RO" water than waste water. This points to a defective seal or cracked membrane.

Is a cracked membrane an internal issue that cannot be detected from a visual inspection?

 

[Water Dog]

Stab in the dark here... are the membranes oriented in the proper direction in the RO housing? The side of the membranes with the two small o-rings on the small plastic tube fitting should be inserted into the housing, thus the large black rubber gasket around the blue membrane cover should be seated nearer to the opening of the membrane housing.

I dunno, just guessing at this point.

 

[TunnelRatt]

Stab in the dark here... are the membranes oriented in the proper direction in the RO housing? The side of the membranes with the two small o-rings on the small plastic tube fitting should be inserted into the housing, thus the large black rubber gasket around the blue membrane cover should be seated nearer to the opening of the membrane housing.

I dunno, just guessing at this point.

Checked them out and everything looks good.