APEX to calIbrate or not to calibrate? this is the question.

[ddc0715]

I preform monthly, by monthly icp tests. i know that my apex measurements are off, based on a comparsion of data, at the time i take my icp sample. simply put; if my apex is testing the water at noon. i take the icp water sample at noon.

Again "i know that my apex measurements are off" when i see the apex data i do math in my head like minus 1 when reading my alk number and so on. i have went as far as to recalibrate the apex, test the water, then pull the icp sample and the icp and apex results are still miles apart(IMO). i dont exspect them to be equal but kinda close would be good.

heres my question or solution-- should I? can i? calibrate my apex to match the icp numbers? would it even make a difference? apex is no what near as accurate as the icp test, but it would be nice to be a bit closer so i dont always have to do math in my head. heres a clip from the last test i did just a few days ago. one can see the harm this could cause if not addressed and or discussed. but again i know the apex reads higher and have never really worried about it.

 

[Formulator]

You can calibrate to whatever you like. I’m not sure I would trust the ICP results as the end-all-be-all accurate result though. ICP is better for trace metals, but the titration methods used in our hobby kits and the apex are actually more reliable for things like alkalinity. Also, you have to wait a week for those ICP results so who knows if they still match your tank water by the time you have the numbers to calibrate with.

Many of us calibrate our trident with tank water using test results from a manual test like salifert. So the short answer is yes, you can calibrate your trident using the ICP results. But I wouldn’t recommend it personally.

 

[areefer01]

I preform monthly, by monthly icp tests. i know that my apex measurements are off, based on a comparsion of data, at the time i take my icp sample. simply put; if my apex is testing the water at noon. i take the icp water sample at noon.

Again "i know that my apex measurements are off" when i see the apex data i do math in my head like minus 1 when reading my alk number and so on. i have went as far as to recalibrate the apex, test the water, then pull the icp sample and the icp and apex results are still miles apart(IMO). i dont exspect them to be equal but kinda close would be good.

heres my question or solution-- should I? can i? calibrate my apex to match the icp numbers? would it even make a difference? apex is no what near as accurate as the icp test, but it would be nice to be a bit closer so i dont always have to do math in my head. heres a clip from the last test i did just a few days ago. one can see the harm this could cause if not addressed and or discussed. but again i know the apex reads higher and have never really worried about it.

You mean run a Trident calibration and use the ICP test results for the numbers you enter on task? No, I wouldn't. I use the calibration solution Neptune provides and run the calibration after I replace B and C. Basically swap out the reagents using the task, let it run 48 to 72 hours, then run through the calibration. I've not run into any issues over the years by following their guild lines. I understand hobbyist user experience of the same equipment can be different but I personally wouldn't recommend doing it that way.

I've seen hobbyist take their respected test kits, run three tests back to back, and use the median as the numbers to enter. I've personally not done that but some around the web have. In my use case the Trident is the source of record so I really don't second guess the results. If I see back to back odd test results then I'll break out the calibration bottle (after I use them I place the date on them for reference later if needed) or use Fauna Marins multi reference and run a manual test to compare.

Interesting enough I do have a recent ICP result set from ATI. Trident and ATI are close. Go figure.

.

 

[gbroadbridge]

I preform monthly, by monthly icp tests. i know that my apex measurements are off, based on a comparsion of data, at the time i take my icp sample. simply put; if my apex is testing the water at noon. i take the icp water sample at noon.

Again "i know that my apex measurements are off" when i see the apex data i do math in my head like minus 1 when reading my alk number and so on. i have went as far as to recalibrate the apex, test the water, then pull the icp sample and the icp and apex results are still miles apart(IMO). i dont exspect them to be equal but kinda close would be good.

heres my question or solution-- should I? can i? calibrate my apex to match the icp numbers? would it even make a difference? apex is no what near as accurate as the icp test, but it would be nice to be a bit closer so i dont always have to do math in my head. heres a clip from the last test i did just a few days ago. one can see the harm this could cause if not addressed and or discussed. but again i know the apex reads higher and have never really worried about it.

You need to understand what ICP can and cannot measure directly.

The ICP measures elements contained in Seawater.

It cannot measure Salinity, Alkalinity, Nitrate or Phosphate.

When an ICP provider lists those numbers on their report, they have obtained the numbers not by ICP but by using another test method.

Alkalinity may have been measured by a titration with a strong acid or indeed they may simply have used a Hanna checker. The Hanna is not likely but mostly you are not told how it was measured so take the number provided with that in mind.

Salinity too is measured using another tool such a lab grade EC meter - or it may have been calculated based on the presences of various ions, but the important thing is that it is not measured directly by ICP.

Similarly with Nitrate, the ICP can measure Nitrogen, but Nitrate is more complex than just that so any number has been measured using another tool.

Same with Phosphate.

To answer your question - I measure those numbers myself using a calibrated device and ignore the numbers on an ICP report.