Help interpreting RODI ICP Results

Rewd · Mar 30, 2022

All,

I recently had icp-analysis.com run ICP testing for my tank. For the tank itself, it came back with a few trace elements "low," so I am working on that separately. But my RODI results puzzle me a little bit. I use a 4 stage purchased from Marine Depot right as they were closing. RO membrane, sediment filter, carbon block and then DI. It also has an in-line TDS meter showing the output TDS which just started reading 1 TDS (has been 0 since installed).

This water was actually sampled from my storage container which is a typical 32 gallon Brute rubber container.

My question is, should I be alarmed by these results? I have been having difficulty with growth, coloration and survivability with some SPS but I attributed that more to high phosphates in my tank itself. Maybe this is a factor? Thoughts?

Dbichler · Mar 30, 2022

Chlorine is the only one I would think would be of any issue. I’m no chemist though. Hopefully others have some valuable insight.

shakacuz · Mar 30, 2022

just to make sure, the results given are from your RODI results?

Rewd · Mar 30, 2022

Yep! These are the RODI.

shakacuz · Mar 30, 2022

Rewd said:
Yep! These are the RODI.

concerning that the RODI has elements, specifically the first 6. RODI water should have nothing. everything should be 0 or VERY close to it.

Woodyman · Mar 30, 2022

Rewd said:
All,

I recently had icp-analysis.com run ICP testing for my tank. For the tank itself, it came back with a few trace elements "low," so I am working on that separately. But my RODI results puzzle me a little bit. I use a 4 stage purchased from Marine Depot right as they were closing. RO membrane, sediment filter, carbon block and then DI. It also has an in-line TDS meter showing the output TDS which just started reading 1 TDS (has been 0 since installed).

This water was actually sampled from my storage container which is a typical 32 gallon Brute rubber container.

My question is, should I be alarmed by these results? I have been having difficulty with growth, coloration and survivability with some SPS but I attributed that more to high phosphates in my tank itself. Maybe this is a factor? Thoughts?

Couple things.

Is that container new?

Did you previously use it to store mixed salt water?

What did you do to 'clean' it when you set it up for RO/DI storage?

Any chance you contaminated the sample with some mixed salt water? Residue on your hands, etc.

Last If nothing else amounts to anything I would verify those results with another company. ICP-analysis while cheap has not been reliable from what I've seen on here.

damsels are not mean · Mar 30, 2022

My money is on contamination somewhere in the chain

ohrmundn · Mar 30, 2022

Rewd said:
All,

I recently had icp-analysis.com run ICP testing for my tank. For the tank itself, it came back with a few trace elements "low," so I am working on that separately. But my RODI results puzzle me a little bit. I use a 4 stage purchased from Marine Depot right as they were closing. RO membrane, sediment filter, carbon block and then DI. It also has an in-line TDS meter showing the output TDS which just started reading 1 TDS (has been 0 since installed).

This water was actually sampled from my storage container which is a typical 32 gallon Brute rubber container.

My question is, should I be alarmed by these results? I have been having difficulty with growth, coloration and survivability with some SPS but I attributed that more to high phosphates in my tank itself. Maybe this is a factor? Thoughts?

Do you mix saltwater in this storage container? ICP recommends not only taking the RODI straight from the line but also rinsing out the vial in RODI as well. Unfortunately, this test will not be 100% accurate because you have contaminated the RODI sample with the brute trashcan. I would replace the DI Resin if the out is reading anything but 0 and make sure to use a flush valve to extend the life of your other filters.

ohrmundn · Mar 30, 2022

ohrmundn said:
Do you mix saltwater in this storage container? ICP recommends not only taking the RODI straight from the line but also rinsing out the vial in RODI as well. Unfortunately, this test will not be 100% accurate because you have contaminated the RODI sample with the brute trashcan. I would replace the DI Resin if the out is reading anything but 0 and make sure to use a flush valve to extend the life of your other filters.

which is good news that the ICP is reading high as it's not a true reflection of your actual RODI.

Rewd · Mar 30, 2022

Will the Brute can contaminate with chlorine, sodium and sulfur? This can has only been used for RODI and absolutely nothing else since the beginning of this tank. I was concerned that maybe the can itself could be an issue, which is why I took the sample directly from there instead of the line. But to see chlorine, sodium and sulfur was not really what I expected. Those don't seem like container contaminants.

My next step is to run another ICP on the line itself. Luckily my local LFS has these kits 50% off so it's a cheap test.

shakacuz · Mar 30, 2022

Rewd said:
My next step is to run another ICP on the line itself. Luckily my local LFS has these kits 50% off so it's a cheap test.

try a different ICP test. Triton or even ATI (this is what i use)

taricha · Mar 31, 2022

Rewd said:
My question is, should I be alarmed by these results? I have been having difficulty with growth, coloration and survivability with some SPS but I attributed that more to high phosphates in my tank itself. Maybe this is a factor? Thoughts?

While it's weird that you are measuring several ppm (1000's of ppb) of Mg, Na, S etc in your RoDi water, it's not a concern to me. Because - even if accurate - it's irrelevant since those amounts will be overwhelmed by your salt mix.

Randy Holmes-Farley · Mar 31, 2022

I do not know if any of the values are accurate. I agree that its not 0-1 ppm TDS water as reported, but I also I do not see an actual problem with it.

FWIW, chlorine in that test is not Cl2, it is chloride, the main component of seawater and most tap water.

My big concern with tap water is copper, and its not detected.

KStatefan · Mar 31, 2022

Don't most of the TDS meters used on RODI systems read in ppt parts per thousand? So convert the higest number Na gives us 0.017 ppt which on every meter I have would show up as 0 TDS