Salinity Calibration and ICP Discrepancy (twice)

[ReeferZ1227]

Good morning,

I obtained an ICP test result from triton on 4/3/24 reading 36ppt.

I obtained an ICP test result from ATI on 4/23/24 reading 37ppt.

I plugged the results into this calculator:
https://monrecifamoi.saulme.fr/salinite/elements_compute_salinity.php
and confirmed the findings @ 36.79ppt

I then mixed 96.65g RODI with 3.69g (overshot .04g) Alessi Sea Salt from the cabinet. I stirred using a magnetic stirrer.

My PinPoint Salinity monitor read my system as 51.5ms, the reference solution as 54ms.

I have attached the Pinpoint Salinity Monitor reference chart:

Any thoughts on the discrepancy, and how I should proceed?

I adjusted/calibrated the salinity monitor to 53ms per the reference solution, however this would further raise my salinity.

Currently planning to adjust the tank to 50ms.

 

[Starbuxxx]

Water evaporates and water gets topped off. That will affect salinity. Dosing some things increases salinity. I top off 1.5 gallons a day, so things are bound to sway.

 

[ReeferZ1227]

Water evaporates and water gets topped off. That will affect salinity. Dosing some things increases salinity. I top off 1.5 gallons a day, so things are bound to sway.

I accidently posted prior to completing the post.

My ato kicks on 4x per day (to prevent flooding) via kasa smart strip. I have no reason to believe I have salinity swings of 2ppt, I have also monitored display/frag/and sump. If anything I should be swinging to the low side as I dose nearly a gallon of kalk (Mrs wages) per day, in addition to 70mL of AFR.

 

[exnisstech]

I would put zero faith in ATI. They sample RODI with their ICP test. I sent two tank samples in along with RODI samples. The rodi samples were taken out of the same container at the same time but the results were totally different. It was my first and last time wasting money on an ICP test. I figure if they can't test RODI I'm sure not changing anything in the tank based on their results. JME

 

[ReeferZ1227]

I would put zero faith in ATI. They sample RODI with their ICP test. I sent two tank samples in a long with RODI samples. The rodi samples were taken out of the same container at the same time but the results were totally different. It was my first and last time wasting money on an ICP test. I figure if they can't test RODI I'm sure not changing anything in the tank based on their results. JME

My RO from ATI tested zinc at ~11.74ug, everything else undetectable. I switched out a half spent mixed bed DI for a full chamber of cation resin hoping to pull the zinc out if it exists and left a mostly fresh mixed bed in chamber #2

I've been battling a tin issue. Triton came back at 45ug. I did 2 20%, 2 50% WC and am at 17ug per ATI. That is inline with expectations as there was 1 week of time unaccounted for (waiting on the initial ICP) and tin could have continued to leach. I changed soft plumbing from. PVC to silicone. I also believe an elevated sump level rusted screws on a fuge light, and replaced that light. I did not have elevated aluminum, zinc, iron nor copper (undetectable on triton). I was thinking it was not rust but the soft plumbing from tieing in a frag tank. Anyone's guess.

 

[Randy Holmes-Farley]

What us Alessi sea salt?

You cannot make a standard using artificial salt mix . It contains variable amounts of moisture.

You seem to have used an incorrect recipe for table salt.where did it come from?

 

[ReeferZ1227]

What us Alessi sea salt?

You cannot make a standard using artificial salt mix . It contains variable amounts of moisture.

You seem to have used an incorrect recipe for table salt.where did it come from?

It's a standard "all natural" table salt from the kitchen. I was under the impression that was the recipe however I did do a quick glance.

Must I procure reagent grade sodium chloride for reference solution?

 

[ReeferZ1227]

I see that I should be using a different standard for a conductivity solution. I used the refractometer solution.

I will use the table salt above at 6.2g : 182g RODI.

 

[ReeferZ1227]

So after calibrating that solution to the pin points 53ms, sump is reading 52.8.

This is where I believed my tank to be resting, for the past 18 months, since buying and calibrating my PinPoint Salinity monitor.

The ICP tests both read high.

The calculator based on the composition of the ICP test reads high.

Thoughts/recommendations? Should I mix my WC salt somewhere around 51ms or 33.7ms and split the difference?

 

[Randy Holmes-Farley]

That salt is probably OK, but I've never assessed a salt like that to see how well it matches normal sodium chloride.

I'd pick up some regular Morton's and see if that is any different. Then, assuming your scale is accurate, I'd go with the Pinpoint if it deviates from the ICP.

 

[ReeferZ1227]

That salt is probably OK, but I've never assessed a salt like that to see how well it matches normal sodium chloride.

I'd pick up some regular Morton's and see if that is any different. Then, assuming your scale is accurate, I'd go with the Pinpoint if it deviates from the ICP.

Added mortons to my order, grabbing two more DI canisters so I can have a cation, anion, and 2 mixed beds at the end. I will do a 3rd round of calibration with Mortons tmrw.

I have an old 53ms Calibration solution but I've "used" it and replaced it in its container a couple times. At the end of the day everything is inline with expectations +/- 1ms - the ATI and Triton tests are the outliers at 1-2ppt.

I'll borrow my buddy's FM Hydrometer for further confluence and continue to use the Pinpoint.

Thanks Randy.

 

[Randy Holmes-Farley]

OK, let us know what you find.

 

[ReeferZ1227]

So my buddies nearly new FM Hydrometer read 1.0275 in the sump and display. This is inline with the ICP test.

Given 2 measurements vs 1, I decided to calibrate my PinPoint to 1.0275 (55.7 from 52.8).

I'll test that against a reference solution using mortons when it arrives.

Ive already backed my salinity down 1ppt. I'll likely do another .5ppt tomorrow evening, after observing the result of the DIY mortons reference. I'll plan to do another .5ppt the following day targeting 35ppt.

Will continue to update the thread, and likely close it with my next triton result in 3-4 weeks.

Thanks Again Randy, it's a privilege.

 

[Randy Holmes-Farley]

You're welcome and thanks for the update!

 

[KStatefan]

What is a FM Hydrometer?

 

[ReeferZ1227]

What is a FM Hydrometer?

My mistake, tropic marin.

High Precision Hydrometer

Ensure that your equipment is reading correctly and your aquarium is at the right salinity with Tropic Marin's High Precision Hydrometer. Many tank inhabitants are sensitive even to minor changes of the water conditions. Unfortunately as we've all experienced, salinity reading equipment as...

www.bulkreefsupply.com

 

[ReeferZ1227]

Mortons solution was looking better, was reading 54ms, went to move the probe and then it just got whacky. I think there may be an intermittent issue with the physical connection between the wire and the probe. Emailed americanmarine for warranty support.

 

[Randy Holmes-Farley]

OK, thanks for the update.

 

[ReeferZ1227]

To close this one out, sent unit to American marine. They sent me what appears to be a brand new unit and/or replaced the probe on the old controller. Turnaround was about a week, hassle free.

Also tossed in a courtesy temp probe and controller, calibrated to NIST standards. Nifty little device, bumped my temp up (over a week or so) by 2 degrees to 80-81 as a result of the confidence in the probe.