ICP test Question

[rob6405]

Will correcting low salinity from an ICP test also fix the low trace elements from the test?

My tank has been running for two years and all the current corals and fish are happy but any new coral i put in dies fairly quickly.

My tank also is mostly softies and anemomes, so its not consuming much alk to dose AFR. Should i just focus on salinity and then retest in a couple months or dose trace now too?

 

[Randy Holmes-Farley Verified Community Expert]

Raising salinity from 26 to 35 ppt (an important thing to do), will raise everything by a factor of 35/26 = 1.35x (except pH and ORP).

That will have an apparently huge effect on things like potassium, calcium and magnesium, but will not bring something that is 0.1 up to a recommended 10 (random example).

This type of icp also cannot determine if you actually have enough of things where it says none detected is normal. It takes ICP-MS for that.

 

[rob6405]

Raising salinity from 26 to 35 ppt (an important thing to do), will raise everything by a factor of 35/26 = 1.35x (except pH and ORP).

That will have an apparently huge effect on things like potassium, calcium and magnesium, but will not bring something that is 0.1 up to a recommended 10 (random example).

This type of icp also cannot determine if you actually have enough of things where it says none detected is normal. It takes ICP-MS for that.

Thank you! I think I'll fix the salinity (slowly) and retest for trace elements in a couple months.

 

[Randy Holmes-Farley Verified Community Expert]

Sounds good. Be sure to elect ICP-MS if trace element quantitation is the goal. :)

 

[Freenow54]

Raising salinity from 26 to 35 ppt (an important thing to do), will raise everything by a factor of 35/26 = 1.35x (except pH and ORP).

That will have an apparently huge effect on things like potassium, calcium and magnesium, but will not bring something that is 0.1 up to a recommended 10 (random example).

This type of icp also cannot determine if you actually have enough of things where it says none detected is normal. It takes ICP-MS for that.

I realize that this result post is dated. For me the results are self explanatory but how does anyone that is not a chemist know what to do to correct things let alone why they got there . To know how to prevent things from reoccurring ?

 

[js-3Design]

I realize that this result post is dated. For me the results are self explanatory but how does anyone that is not a chemist know what to do to correct things let alone why they got there . To know how to prevent things from reoccurring ?

Calibrate your salinity meter.
Also, test your tests.

For trace elements, on every bottle there is dosage information.

 

[Randy Holmes-Farley Verified Community Expert]

I realize that this result post is dated. For me the results are self explanatory but how does anyone that is not a chemist know what to do to correct things let alone why they got there . To know how to prevent things from reoccurring ?

Sorting out chemistry issues that have always been challenging for many folks is a main reason reef chemistry forums have long existed. :)

 

[Freenow54]

Sorting out chemistry issues that have always been challenging for many folks is a main reason reef chemistry forums have long existed. :)

I am looking at the posts but they so far are dealing with specific issues . I suppose a book or complete article would be hard to make since there probably so many variables. Like a flow chart if possible is this happening ? no go right , yes go left

 

[Randy Holmes-Farley Verified Community Expert]

I am looking at the posts but they so far are dealing with specific issues . I suppose a book or complete article would be hard to make since there probably so many variables. Like a flow chart if possible is this happening ? no go right , yes go left

Most icp companies do provide guidance on how to respond, particularly when it involves dosing more of soemthing they sell.

I do understand that in some cases with multiple things needing fixing at once, it gets more complicated on what to do first.

Some are actually very difficult to solve, such as magnesium too high and salinity too low, which is a trap one can get into with inaccurate mag and salinity testing. There's no easy answer except substantial water changes.

 

[Freenow54]

Thank You for answering although to me Substantial is a huge word considering the " distillation " like approach . It would take weeks I would think. Repeated tests chasing something that may never be achieved

 

[Freenow54]

I do sincerely appreciate the answer . But there must be something better as to head off such off the scale readings

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure what problem we are trying to head off, but as noted above by js-3Design,:

1. Make sure your salinity measurement is reasonably accurate, and keep on top of it.

2. Make sure any tests you use for dosing are plausibly accurate, by comparing to ICP or just new salt water or standards.

3. I'd also add a different one: use as few tests as possible. Less to go wrong. For example, I dose AFR on alk measurement that I am very confident in, and do not measure calcium or magnesium at all (except by ICP if I do one).