RO/DI question

[Treebeard]

I have an Aquasafe unit with 3 DI resin canisters which has been in use for about a year. A couple of months ago I changed all three filters and the resin because TDS was creeping up in my water and the output was getting very low. The instructions indicated that the RO membrane should last for at least two years so I did not change it. However, my output was still low and I could not get TDS below 10ppm so last night I changed the RO membrane as well. Now things are even worse. I cannot get TDI below 15ppm and the flow restrictor which is supposed to put back-pressure on the membrane seems to have no affect.

Which component of the system reduces TDI? Is it possible my that my resin is contaminated and needs to be changed again?

[hillegom]

Do you mean you have 3 DI resin canisters in addition to a particle and carbon canisters?
Depending on the type of membrane you have, the carbon protects the membrane from chlorine. Some DI resins change colour when exhausted, so it is easy to see how close to the end you are.
The flow restrictor has to be matched to your membrane, ie a 100 gpd membrane has a different restrictor than a 50 gpd unit.
What is the tdi or your feed water?

[Treebeard]

There are three particle and carbon canisters, followed by the RO membrane and three DI resin canisters. I think the resin is supposed to change from green to brown when it is exhausted, but it always has looked brownish to me.

I am not sure about the flow restrictor. I ordered the replacement membrane from the same place I ordered the system, so I would assume he would send the correct replacement membrane. The restrictor is adjustable, but even setting it wide open in flush position, there is still water coming out the clean water line. With the old membrane opening it all the way would result in zero output. Closing it all the way would result in maximum output with dirty water.

I cannot recall what the tds is of the raw water, but I am guessing it is around 50ppm. I will check it at lunchtime.

Originally Posted by hillegom

Do you mean you have 3 DI resin canisters in addition to a particle and carbon canisters?
Depending on the type of membrane you have, the carbon protects the membrane from chlorine. Some DI resins change colour when exhausted, so it is easy to see how close to the end you are.
The flow restrictor has to be matched to your membrane, ie a 100 gpd membrane has a different restrictor than a 50 gpd unit.
What is the tdi or your feed water?

[Myka]

What's the TDS of your tap water?

Can you take a picture of your unit (oh that sounds bad!! ), or provide a link to your exact one? As hillegom pointed out, I'm wondering if you have confused the DI cartirdges for particulate and carbon filters. The order should be: particulate, carbon, RO, DI. Once the water passes through the RO it should not be greater than 20ppm or it will exhaust the DI resin very quickly, and will not get it down to 0 ppm TDS. Try disconnecting the hose feed between the RO and the DI and test the water coming out of there (collect it in a clean cup for ease of testing). If it is greater than 20 ppm or approaching 20ppm I would suggest you add a second RO cartridge. This would probably only be a problem if your tap water has really high TDS which is very possible where you live.

EDIT: You have a 7 stage filter system? There is no reason to have a system that large for tap water with a TDS of 50 ppm. My tap water is 90-95 ppm, and my 4 stage (particle, carbon, RO, DI) gets my product water to 0 ppm TDS. I am wondering if your adjustable flow restrictor is faulty...I have never seen one of those before, and I am leary about how it may work.

[Treebeard]

I will try to supply a picture when I go home for lunch.
I have the order exactly as you stated below. It is possible that I exhausted the DI resin because I did not change the membrane at the same time I changed the resin and particulate filters, but the guy from Aquasafe said the membrane should last for 12-24 months.

I will also test the raw water and the water after the membrane.
It is a 7 stage filter, if I understand correctly. There are three canister filters, followed by the RO membrane, followed by three DI canisters.
I agree with your comments on this adjustable flow restrictor. It is a real pita to set correctly. What kind of system are you using?

Originally Posted by Myka

What's the TDS of your tap water?

Can you take a picture of your unit (oh that sounds bad!! ), or provide a link to your exact one? As hillegom pointed out, I'm wondering if you have confused the DI cartirdges for particulate and carbon filters. The order should be: particulate, carbon, RO, DI. Once the water passes through the RO it should not be greater than 20ppm or it will exhaust the DI resin very quickly, and will not get it down to 0 ppm TDS. Try disconnecting the hose feed between the RO and the DI and test the water coming out of there (collect it in a clean cup for ease of testing). If it is greater than 20 ppm or approaching 20ppm I would suggest you add a second RO cartridge. This would probably only be a problem if your tap water has really high TDS which is very possible where you live.

EDIT: You have a 7 stage filter system? There is no reason to have a system that large for tap water with a TDS of 50 ppm. My tap water is 90-95 ppm, and my 4 stage (particle, carbon, RO, DI) gets my product water to 0 ppm TDS. I am wondering if your adjustable flow restrictor is faulty...I have never seen one of those before, and I am leary about how it may work.

[Myka]

Originally Posted by Treebeard

I will try to supply a picture when I go home for lunch.
I have the order exactly as you stated below. It is possible that I exhausted the DI resin because I did not change the membrane at the same time I changed the resin and particulate filters, but the guy from Aquasafe said the membrane should last for 12-24 months.

I will also test the raw water and the water after the membrane.
It is a 7 stage filter, if I understand correctly. There are three canister filters, followed by the RO membrane, followed by three DI canisters.
I agree with your comments on this adjustable flow restrictor. It is a real pita to set correctly. What kind of system are you using?

I have an AquaFX Barracuda 4 stage was $180 I think. Your first three cartridges (I'm assuming one particulate and two carbons?) should be changed every 6 months no matter what. The RO should last the longest, but it's hard to pinpoint how long it will last. Be sure when you do replace it that you replace the first three just before replacing the RO. The DIs will last varying amounts of time as well given how much TDS is reaching them. Measure the TDS of the water after the RO but before the DIs as I described above, and the tap water, and we can go from there.

[hillegom]

When you change your particle and carbon filters, disconnect the feed line to the RO.
After the filters are changed, flush water through and catch the effluent. A lot of times, the water will have small particles of carbon "dust" that could screw up the RO membrane and/or the flow restrictor. When the effluent, is clear, shut off the water and reconnect the line to your RO. Possibly, you have some small particles stuck where they should not be

[hillegom]

Forgot to mention, if you have an incoming TDI of 50, a reading of 0 output is easily attainable.

[Myka]

Originally Posted by hillegom

When you change your particle and carbon filters, disconnect the feed line to the RO.
After the filters are changed, flush water through and catch the effluent. A lot of times, the water will have small particles of carbon "dust" that could screw up the RO membrane and/or the flow restrictor. When the effluent, is clear, shut off the water and reconnect the line to your RO. Possibly, you have some small particles stuck where they should not be

What he said. I should have mentioned that...sorry.

[Treebeard]

Apparently my memory is not what it once was, or maybe it never was....anyways my raw water is 276. TDS after the RO membrane is 20.
I did not have time to take a picture, but from the instructions it is a 5 stage system:

1. 5 micron sediment
2. Carbon
3. 5 micron coconut carbon
4. RO membrane
5. DI cartridges (3)

At the beginning it was reducing TDS to 0.
When I changed the carbon and sediment filters, and the DI resin, I did not change the RO membrane, nor did I disconnect and flush the filters.

Is my RP membrane ruined, or can I flush it out? As I said previously, I am also having trouble with the flow restrictor so I guess it is also screwed up. Your explanations would explain the problem.