RO/DI help

[GraffitiSpotCorals]

Skimmed through some and just thought I would share...

 

I had bought the same I line Tds meter and it did NOT come calibrated it actually doesn't even calibrate. So grab a second meter and double check it before you get to involved like I did.

 

I also ordered a system which came with the wrong flow restrictor for the membrane it came with. So make sure your flow restrictor is correct.

[.OptimusPrime.]

What's the TDS before the DI stage?

 

Sorry, been busy lately and haven't to fixing this yet. This is what BRS asked and I just happened to know it is showing 4 TDS after about running for 15-20 mins.

 

Try reversing the probes on the TDS to confirm that the meter is not the problem. I have a spectrapure unit and for mine you need a higher resistance insert for the waste line with higher output membranes. Might double check that BRS doesn't have a similar requirement if that wasn't part of the upgrade kit.

 

Reversed the probes and got the same results.

 

Have you checked to see if both membranes are fully seated in their housings? If the O-ring is not making a good seal, waste-water will bypass the ring and increase TDS. Also, if there's a valve on the flow restrictor, is it set in the right position?

 

I opened the new membrane up and reseated it. I did not touch the old membrane as it was functioning correctly. I did noticed that the Out line from the new membrane was not properly secured as I was able to just take it out with a slight pull. Would that have caused any issue?

 

Skimmed through some and just thought I would share...

 

I had bought the same I line Tds meter and it did NOT come calibrated it actually doesn't even calibrate. So grab a second meter and double check it before you get to involved like I did.

 

I also ordered a system which came with the wrong flow restrictor for the membrane it came with. So make sure your flow restrictor is correct.

 

Do you know how to calibrate them? I was at the LFS yesterday to get RO/DI water and the TDS meter totally skipped my mind.

 

I got my new DI resin in from BRS today, should I go replace it and see if it make a difference?

 

 

[Origami]

I opened the new membrane up and reseated it. I did not touch the old membrane as it was functioning correctly. I did noticed that the Out line from the new membrane was not properly secured as I was able to just take it out with a slight pull. Would that have caused any issue?

It very well could have. I normally have to practically wrestle the membrane out of the housing using a pair of pliers. If it was not seated well, then waste water would have mixed with your "pure water" and it would be pretty much like not having the RO membranes (either one) in there in the first place. Reseating it may help.

[hypertech]

I think he means the tubing wasn't tight in the fitting. The only problem that might cause is a leak.

[.OptimusPrime.]

I think he means the tubing wasn't tight in the fitting. The only problem that might cause is a leak.

 

Yeah that's what I meant, the tubing connecting the Second membrane to the T fitting before the DI resin was loose.

[Origami]

No, that shouldn't have been the problem, then.

 

If you're only getting 4-5 TDS going into the DI stage, you shouldn't be seeing so much exhaustion so quickly under normal circumstances. You mentioned above that this was over 15-20 minutes, though. What does it start out at and how long does it take to drop to 4-5 TDS? Is really should come down fairly fast - much less than 15 minutes. Also, are you able to get a good pH measurement of the RO water (before the DI stage)? By any chance, are you on a well? Does the rapid resin depletion correspond with anything else besides the 150 gpd upgrade? Did you flush the new membrane for 20 minutes or so before adding the DI stage?

[.OptimusPrime.]

No, that shouldn't have been the problem, then.

 

If you're only getting 4-5 TDS going into the DI stage, you shouldn't be seeing so much exhaustion so quickly under normal circumstances. You mentioned above that this was over 15-20 minutes, though. What does it start out at and how long does it take to drop to 4-5 TDS? Is really should come down fairly fast - much less than 15 minutes. Also, are you able to get a good pH measurement of the RO water (before the DI stage)? By any chance, are you on a well? Does the rapid resin depletion correspond with anything else besides the 150 gpd upgrade? Did you flush the new membrane for 20 minutes or so before adding the DI stage?

 

It starts around 30 and drops to 4-5 TDS. It probably took less than 5 to come down, but I ran it longer just to see how low it would go.

 

I will check the pH and report back. I did let the unit run for about 30 minutes when I installed the second membrane (don't know if that qualifies as flushing), however it ran with all new filters/di resin installed.

 

and even after the first 20 gallons I made after the initial 30 min run the DI resin didnt show any kind of exhaustion.

[.OptimusPrime.]

so quick update:

 

Tested the pH and it came back as normal around 8.

 

I replaced the resin and let it run for a few minutes. OUT reading is now 0 TDS again. Made 20 gallons all 0 tds.

 

I did notice something that I didnt notice or didnt seem like a big deal before.

 

Does the water level in your DI resin ever change? When the unit is running the water in the DI resin is about 3/4 of the way full and while the unit is off it drops to about to about 1/2 of the canister.

 

Is this normal? The other filters are always full to the max. I don't can't recall correctly if the DI chamber was like this before I installed the upgrade or not. But I want to say the DI chamber as full 100% of the time as well.

[Origami]

I've had an air pocket develop like this before. It always made me wonder where the air was coming from. I can't say off hand if it would affect performance the way you're seeing, though. You may want to try bleeding it out and seeing if it makes a difference.

 

By the way, I asked about the pH because I recently read that some systems on wells have low pH water coming in. The CO2 in the water brings the pH down and really cuts down on DI resin life (because it's picked up there). A couple of years ago, DaveS (who is on a well and had low pH water) had an issue with his DI resin depleting quickly and this may have been the reason.

[hypertech]

My DI runs about half full of air. It always has. That's all the pressure it needs to push the water through the resin and to the storage bin. The air level changes a bit depending on if its just starting up, etc, but its never caused a problem for me.

[.OptimusPrime.]

I've had an air pocket develop like this before. It always made me wonder where the air was coming from. I can't say off hand if it would affect performance the way you're seeing, though. You may want to try bleeding it out and seeing if it makes a difference.

 

By the way, I asked about the pH because I recently read that some systems on wells have low pH water coming in. The CO2 in the water brings the pH down and really cuts down on DI resin life (because it's picked up there). A couple of years ago, DaveS (who is on a well and had low pH water) had an issue with his DI resin depleting quickly and this may have been the reason.

 

 

My DI runs about half full of air. It always has. That's all the pressure it needs to push the water through the resin and to the storage bin. The air level changes a bit depending on if its just starting up, etc, but its never caused a problem for me.

 

 

Well I am on city/county water so that throws the well scenario out.

 

Thanks for clearing up the air pocket issue, makes me feel better. I made 20G yesterday and didn't have any issues. Maybe it was just a fluke. Guess time will tell.