RODI only producing waste water

[Hitman]

If the membrane dried out it’s shot. I agree replace it and see.

 

[leroy_jenkinz]

Weird your TDS is that high though. And I'm guessing he made more than 50 Gallons with that unit lol

Yea I'm thinking he used it until it was time to replace the filters which coincided with his move/selling the tank. I'm ok with it though I still saved a bunch of money as long as buying a new membrane fixed the issue which I think it will. I might need to replace all the filters to be safe

 

[Captain Quint]

Yea I'm thinking he used it until it was time to replace the filters which coincided with his move/selling the tank. I'm ok with it though I still saved a bunch of money as long as buying a new membrane fixed the issue which I think it will. I might need to replace all the filters to be safe

I agree with you leroy_jenkinz. It will cost roughly $90 give or take. Membranes are what cost the most but generally do not need to be changed on an average of once every two years. Sediment filters are inexpensive, carbon blocks not expensive either.

Do this and your unit will be almost good as new.

*Average on replacement in case you wonder.

1, Sediment ~every 6 months (so buy 2)
2. Carbon blocks ~ once a year
3. Membrane about every two years
4. DI resign when you notice TDS go up from 0

*this may all vary just a bit depending on how much water you make and condition of water being used*

 

[leroy_jenkinz]

Ok everyone after this ill stop bothering everyone but im determined to find a solution lol. I keep tinkering with it and i think the problem is pressure and not the membrane and this is why:

The TDS reading of 65 which i thought was after the membrane was actually only after the filters. I used my Line 2 test after the membrane and it fluctuated between 2-3. I took the membrane out completely just to test the pressure and the water flowed out of the canister no problem. I instert membrane and bam low flow. I think my 40psi just isnt enough to get it to the DI canisters. If anyone has any input id gladly accept it but i promise i wont bug anyone anymore as i truly believe this is the issue ( even though i am a novice at all this )

 

[KStatefan]

If it is only producing waste water how are you getting a reading after the membrane?

 

[leroy_jenkinz]

If it is only producing waste water how are you getting a reading after the membrane?

The hose that would normally go to the Di canisters, i unplugged that and inserted one of my extra TDS reading hoses. My TDS reader(monitor) has 3 lines.

 

[Captain Quint]

Ok everyone after this ill stop bothering everyone but im determined to find a solution lol. I keep tinkering with it and i think the problem is pressure and not the membrane and this is why:

The TDS reading of 65 which i thought was after the membrane was actually only after the filters. I used my Line 2 test after the membrane and it fluctuated between 2-3. I took the membrane out completely just to test the pressure and the water flowed out of the canister no problem. I instert membrane and bam low flow. I think my 40psi just isnt enough to get it to the DI canisters. If anyone has any input id gladly accept it but i promise i wont bug anyone anymore as i truly believe this is the issue ( even though i am a novice at all this )

You are not bothering anyone, good sir.

We're glad you are here.

 

[leroy_jenkinz]

You are not bothering anyone, good sir.

We're glad you are here.

haha thanks man, i appreciate everyones input and insight. Im sure this issue has been brought up before and hate to ask the same repeat question. I think i finally found the answer and just wanted to make sure before i dropped another 100+ on a booster pump.

 

[KStatefan]

The hose that would normally go to the Di canisters, i unplugged that and inserted one of my extra TDS reading hoses. My TDS reader(monitor) has 3 lines.

If there is no water there it is not going to read correctly

 

[leroy_jenkinz]

If there is no water there it is not going to read correctly

There is water it's just a really slow trickle does that still give a improper reading also are bad membranes known to hindrance water pressure? That's why I think a booster pump will solve the issue

 

[KStatefan]

I do not know what brand of membrane you have but Filmtec membranes are rated at 50 psi but will still produce at lower psi. At you 45psi should be close to rated flow.

Water is not going to be running fast. Waste water should be 4 times the good water.

 

[leroy_jenkinz]

Gentlemen I cant thank yall enough. So after googling my mwbranr the specs call for 60 psi. So looks like next pay check I'll be buying a booster pump. Thanks for all the tips and suggestions, hopefully one day I can do the same to someone who is new to the hobby

 

[wlittlefield]

A booster pump will do wonders for you. I run one and it A. makes my RODI machine work B. dramatically cuts down on waste water which is amazing.

I'd also encourage you to change out the filters before the DI resin. If you're reading 65 TDS before the membrane I think they are shot. With that level of TDS hitting your membrane, you'll burn through it quickly.

This is the booster pump I got: https://www.bulkreefsupply.com/1-4-aquatec-8800-booster-pump-kit.html

It isn't cheap or very much fun to buy but it has worked well.

 

[KStatefan]

A booster pump will do wonders for you. I run one and it A. makes my RODI machine work B. dramatically cuts down on waste water which is amazing.

I'd also encourage you to change out the filters before the DI resin. If you're reading 65 TDS before the membrane I think they are shot. With that level of TDS hitting your membrane, you'll burn through it quickly.

This is the booster pump I got: https://www.bulkreefsupply.com/1-4-aquatec-8800-booster-pump-kit.html

It isn't cheap or very much fun to buy but it has worked well.

Pre filters do very little in reducing the TDS before the membrane. I would bet most people have higher than 65 TDS hitting their membrane I know I do 280 for me.

 

[leroy_jenkinz]

A booster pump will do wonders for you. I run one and it A. makes my RODI machine work B. dramatically cuts down on waste water which is amazing.

I'd also encourage you to change out the filters before the DI resin. If you're reading 65 TDS before the membrane I think they are shot. With that level of TDS hitting your membrane, you'll burn through it quickly.

This is the booster pump I got: https://www.bulkreefsupply.com/1-4-aquatec-8800-booster-pump-kit.html

It isn't cheap or very much fun to buy but it has worked well.

yea i would definitely like to just have my rodi machine work haha. i read about them and all the benefits especially the waste to product ration, but i was hoping my home water pressure would be suffice but oh well. Ok ill look into those as they are pretty cheap anyways in the grand scheme of things

 

[PhreeByrd]

Gentlemen I cant thank yall enough. So after googling my mwbranr the specs call for 60 psi. So looks like next pay check I'll be buying a booster pump. Thanks for all the tips and suggestions, hopefully one day I can do the same to someone who is new to the hobby

I have to say that I did not look up the specs on that membrane, but I also need to say that I've never seen an R/O membrane for this type of use that requires 60 psi. 60psi is above the static water pressure of almost all municipal water supplies, and far above the residual pressure. Most R/O membranes will work just fine at 40psi, although throughput will probably be below the membrane's stated (maximum) production rate. I highly doubt that the issue is pressure.

I think it's far more likely that the membrane is clogged. I did not see anything in your plumbing to allow you to backflush the membrane, and this is necessary maintenance with most systems.

I would seriously consider replacing the membrane first.

 

[KStatefan]

I do not know of a residential system that has a backflush capability. In the Op first pick it show a flush valve but it does not backflush.

I agree with the pressure and that a new membrane should be replaced

 

[WVNed]

A simple way to think of a RO/DI is the letter Y. It represents the path of water through the filter
Y
Below the fork is the incoming tap water. This leg has all the filters before the membrane and all the water goes straight through them.
The point where the 3 legs connect is the membrane canister.
The top heavy leg is the waste water out. This has the flow restrictor in it. The flow restrictor maintains pressure in the membrane canister against the membrane so water will be forced through it.
The lighter leg of the Y is where the product water comes out. It has the DI canister in it so all product water goes through it.

The U shaped line with the valve is the flush valve. It would be off the side of the heavy leg of the Y. It bypasses the flow restrictor. This makes the water flow faster at lower pressure through the membrane canister and washes the side of the membrane exposed to tap water off. This extends the life of the membrane.

It is normal to get up to 4 times as much waste water out as product water. So at low pressure the water you want may be very little. A TDS of 2-5 is fine after the membrane before the DI canister.
The DI canister should remove the rest and give you 0 out.
Take 2 glasses the same size and catch the product water in one and the waste in the other. Start them at the same time and stop when one gets full. You can then see your rejection fraction and tell if it is off.

If it is off or the TDS after the membrane is higher than 5 or so I would replace both the membrane and the flow restrictor. The flow restrictor must be correctly sized for the membrane you are using in gallons per day.

I run my system at 80psi and get more than 100 out of the tap so I dont use a booster pump. It will still make water at 40 but it is a lot less.

 

[leroy_jenkinz]

I have to say that I did not look up the specs on that membrane, but I also need to say that I've never seen an R/O membrane for this type of use that requires 60 psi. 60psi is above the static water pressure of almost all municipal water supplies, and far above the residual pressure. Most R/O membranes will work just fine at 40psi, although throughput will probably be below the membrane's stated (maximum) production rate. I highly doubt that the issue is pressure.

I think it's far more likely that the membrane is clogged. I did not see anything in your plumbing to allow you to backflush the membrane, and this is necessary maintenance with most systems.

I would seriously consider replacing the membrane first.

I do not know of a residential system that has a backflush capability. In the Op first pick it show a flush valve but it does not backflush.

I agree with the pressure and that a new membrane should be replaced

i know im new to the hobby and i appreciate the insight but i think based on my trial and errors and the specs for the membrane clearly say 60psi for functionality i think buying a new membrane would be the illogical decision. It also is reading 2 TDS after the membrane so isnt that a clear sign that the membrane is still functioning? The Booster pump is already an upgrade to any ones system regardless of their natural house pressure so me buying a booster will a) either solve my problem AND ill have a more productive system or b) it wont solve my problem and ill need a new membrane and ill still have a booster for a productive system. But im pretty sure A is the correct scenario

 

[PhreeByrd]

I do not know of a residential system that has a backflush capability. In the Op first pick it show a flush valve but it does not backflush.

I agree with the pressure and that a new membrane should be replaced

Good catch, KStatefan. I should not have used the word 'backflush' -- don't know why I did -- but you are right.