Reading icp test results

[TonyB13]

Help my sodium came back high. 

My triton icp test days my sodium is 12341 mg/l I have no idea what that means. How do I translate that to the reading on my refractromerer.

Thanks 

[WheresTheReef]

Not sure how the ICP result translates to salinity, but I would guess it is likely elevated. I haven’t used Triton, but used ICP Analysis before. My Na and Cl were high on a test. Once I calibrated my refractometer I saw that my salinity was up pretty high. Do you calibrate your refractometer with a solution?

Edited January 31, 2021 by WheresTheReef

[TonyB13]

Well I always calibrate my refractometer I guess I will have to get another one for comparison. 

[Origami]

Tony don't calibrate your refractometer based on an ICP test. Use a refractometer calibration solution.



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[TonyB13]

I did but I just really would love to know how far I was off.thanks Tom 

I wonder if triton would be able to tell me?

[Origami]

Tony, ICP doesn't measure salinity. The technique forms a plasma and reads out the element concentration of the sample under test. It doesn't directly tell you where that sodium or chloride ion came from, for example because the whole sample is broken up into it's elemental parts in the process. It's like having a lego model under a sheet and breaking it apart to the individual bricks and then trying to piece together what it was before you took it apart. Software and other models are used to analyze the major and trace ions in your tank water. But, for ions like sodium and chloride, I'd not trust the process to give you a decent salinity estimate. At least, not to make any deductions that I'd apply to my other test gear or to change tank salinity or alkalinity..... Just my two cents.

[Origami]

BTW, sodium makes up about 30% of the ions in normal seawater. It's normally present at about 10,500 ppm. If the Triton test for sodium was accurate and it correlated with a commensurate level of elevated chloride (which would be present in your water at about 22,200 ppm), it would represent a salinity of about 41 ppt (or 1.031 sg) versus the normal 35 ppt (1.0264 sg). Bottom line: Test with a calibrated refractometer. If you don't trust it, get some new calibration solution or make your own. If you get confirmation of the high salinity, that's when you should take action. I'd be very hesitant to dilute my water by that much (because it could be very hard on many corals) without cross-checking the measurement. 

 

Also, if the tank has been running using only two-part dosing over many years with high alkalinity consumption, it's possible that both sodium and chloride can begin to drift upward relative to the other ions in the water. That's because the sodium bicarbonate (in the alk part) and the calcium chloride (in the calcium part) add sodium and chloride ions that just accumulate. Without periodic large water changes, you can get into a situation where your sodium (and chloride) levels are out of proportion with the other ions.