Marinlabs icp results

[Randy Holmes-Farley Verified Community Expert]

Yes, you need to freeze and thaw the whole thing. Removing some very saline water while there is still ice will cause the final values to all be low.

 

[Cory]

Yes, you need to freeze and thaw the whole thing. Removing some very saline water while there is still ice will cause the final values to all be low.

Okay i will redo the test when I get home and freeze another sample. I just wanted to see what the results were half way unthawed. Do you think it should be colder than -23c?

 

[Randy Holmes-Farley Verified Community Expert]

Okay i will redo the test when I get home and freeze another sample. I just wanted to see what the results were half way unthawed. Do you think it should be colder than -23c?

The colder it gets, the more extreme is the test. Some papers I've read suggest that it isn't fully "frozen" until at least -36 deg C.
https://www.sciencedirect.com/science/article/pii/S0165232X99000336

 

[Cory]

The colder it gets, the more extreme is the test. Some papers I've read suggest that it isn't fully "frozen" until at least -36 deg C.
https://www.sciencedirect.com/science/article/pii/S0165232X99000336

Last night was -28 C. So close. When i get home from work I cab do the test.

I tested the first samples salinity when it was fully unthawed just out of curiosity, and it still read 43ppt. Why wouldnt the salinity go back to normal? Is the atc on the refractometer broken? It was cold.

 

[Randy Holmes-Farley Verified Community Expert]

Last night was -28 C. So close. When i get home from work I cab do the test.

I tested the first samples salinity when it was fully unthawed just out of curiosity, and it still read 43ppt. Why wouldnt the salinity go back to normal? Is the atc on the refractometer broken? It was cold.

It will be back to normal. Not sure why you got an off value, but it may be beyond the ATC range of the refractometer.

 

[Cory]

It will be back to normal. Not sure why you got an off value, but it may be beyond the ATC range of the refractometer.

Okay ill make sure the temperature is the same as tank water.

 

[Cory]

http://www.reefcentral.com/forums/showthread.php?t=1007891&highlight=conductivity&page=3

Remember this thread Randy? Lol i was boxfishpooalot back then.

What came to my mind, would a conductivity meter show faulty salinity measurments if sodium was low and sulphur was high like in my icp results? My rational is that sodium and sulphur have different electrical charges at greater or lesser concentrations and this may effect a conductivity probe. No?

 

[Cory]

So heres the results of fully unthawed water at room temp.

35ppt
10.2 dkh
520 calcium
1350 magnesium

Tank water calcium 480ppm

So what do you think? Their reults were not effected?

Id like to add sodium chloride to boost the sodium. Viable idea? How much would i add for 200 net gallons?

 

[Randy Holmes-Farley Verified Community Expert]

http://www.reefcentral.com/forums/showthread.php?t=1007891&highlight=conductivity&page=3

Remember this thread Randy? Lol i was boxfishpooalot back then.

What came to my mind, would a conductivity meter show faulty salinity measurments if sodium was low and sulphur was high like in my icp results? My rational is that sodium and sulphur have different electrical charges at greater or lesser concentrations and this may effect a conductivity probe. No?

Well, that's a complicated question. I think your salinity must be low (if the ICP values are correct), but if you want to discuss if conductivity might still be "off" of the actual low salinity, then we can.

Sodium low and sulfur high are not "caused" by each other. They can each move up or down independently in seawater.It's not like they trade off against each other the way chloride and sulfate would (at fixed salinity).

So part of the question is, if sulfate is high (at fixed salinity), then chloride must be low to maintain the same total number of negative charges to be the same (since together they comprise the huge majority of negative charges in seawater).

The question is then how conductive are two chloride ions relative to one sulfate?

There are a variety of ways to compare them, but two chloride ions in dilute solution are close in conductivity to one sulfate ion in dilute solution:
see the table here
https://en.wikipedia.org/wiki/Conductivity_(electrolytic)

Does that exactly hold in seawater? Not sure, but I'd guess that conductivity used to measure the salinity of seawater will not be far off just because one swaps out 2 units of chloride for one of sulfate at the levels you have.

The sodium issue is more complicated, since the salinity must actually be low. We can see all the main things that sodium could be swapped for (magnesium, calcium, potassium) and those are not high enough to simply have been swapped for sodium ions to make sodium low and those high.

 

[Cory]

Well, that's a complicated question. I think your salinity must be low (if the ICP values are correct), but if you want to discuss if conductivity might still be "off" of the actual low salinity, then we can.

Sodium low and sulfur high are not "caused" by each other. They can each move up or down independently in seawater.It's not like they trade off against each other the way chloride and sulfate would (at fixed salinity).

So part of the question is, if sulfate is high (at fixed salinity), then chloride must be low to maintain the same total number of negative charges to be the same (since together they comprise the huge majority of negative charges in seawater).

The question is then how conductive are two chloride ions relative to one sulfate?

There are a variety of ways to compare them, but two chloride ions in dilute solution are close in conductivity to one sulfate ion in dilute solution:
see the table here
https://en.wikipedia.org/wiki/Conductivity_(electrolytic)

Does that exactly hold in seawater? Not sure, but I'd guess that conductivity used to measure the salinity of seawater will not be far off just because one swaps out 2 units of chloride for one of sulfate at the levels you have.

The sodium issue is more complicated, since the salinity must actually be low. We can see all the main things that sodium could be swapped for (magnesium, calcium, potassium) and those are not high enough to simply have been swapped for sodium ions to make sodium low and those high.

Thanks. That was a complicated question! I raised my magnesium to 1300 using magnesium chloride from 1130ppm. Used 500 grams of magnesium chloride anahydrous. I also raised my calcium with calcium chloride to 450 ppm from 386ppm. 136 grams, kent turbo calcium. Was that correct to do since sulfur is high?

I think even if their results are off my tank shouldnt suffer if I raise it a bit right?

I got some food grade sodium chloride. The ingredients just say soduim chloride. Nothing else. Its granulated so they dont even need to add anti caking agent.

How much sodium chloride would you add to 200 net gallons?

 

[Cory]

Marinlabs said they measure salinity with a refractometer. 28ppt. How did they get such a low value is confusing.

I did a salinity calculation with that web page jim welsh posted, it came to 29.65 ppt.

 

[Randy Holmes-Farley Verified Community Expert]

The chloride salts were appropriate additions. The sodium chloride could be fine too.

Not sure why the different tests don't line up better.

 

[Cory]

The chloride salts were appropriate additions. The sodium chloride could be fine too.

Not sure why the different tests don't line up better.

Thanks Randy

Can you please tell me how much sodium chloride to add? I literally dont have a clue how to calculate that.

Is there some additional information you need?

Im thinking even if i bring up the salinity to red seas values at 1.029 ish there shouldnt be any problems with the livestock if theres an error on their part.. But im not sure how much that would be. Is there a calculator some place?

 

[Randy Holmes-Farley Verified Community Expert]

You cannot correct the sulfate by addition without salinity getting way too high.

Thanks Randy

Can you please tell me how much sodium chloride to add? I literally dont have a clue how to calculate that.

Is there some additional information you need?

Im thinking even if i bring up the salinity to red seas values at 1.029 ish there shouldnt be any problems with the livestock if theres an error on their part.. But im not sure how much that would be. Is there a calculator some place?

You cannot completely correct the sulfate by addition without salinity getting way too high.

What is your estimated water volume?

 

[Cory]

You cannot correct the sulfate by addition without salinity getting way too high.


You cannot completely correct the sulfate by addition without salinity getting way too high.

What is your estimated water volume?

Okay. Its approximately 200 gallons. And thats an under estimate.

 

[Randy Holmes-Farley Verified Community Expert]

If you have 200 gallons (757 liters) and you want to raise sodium by 1884 ppm, from your value (8916 ppm) to the typical sodium in 35 ppt seawater (10,800 ppm), you'd need to add:

1,884 mg/L sodium x 757 L = 1.43 kg of sodium or 5.1 kg of sodium chloride.

That will raise salinity by 5,100 g/757 L = 6.1 ppt

That would also, coincidentally, put you close to 35 ppt.

So it is a reasonable experiment if you are sure your salinity is low, but not so reasonable if you think it is already OK and the ICP company messed up (maybe they confused your sample with someone else lol).

If you did it, I'd spread it out over at least a couple of weeks. Maybe do half or a quarter and then pause to make sure nothing seems to be going wrong.

 

[Cory]

If you have 200 gallons (757 liters) and you want to raise sodium by 1884 ppm, from your value (8916 ppm) to the typical sodium in 35 ppt seawater (10,800 ppm), you'd need to add:

1,884 mg/L sodium x 757 L = 1.43 kg of sodium or 5.1 kg of sodium chloride.

That will raise salinity by 5,100 g/757 L = 6.1 ppt

That would also, coincidentally, put you close to 35 ppt.

So it is a reasonable experiment if you are sure your salinity is low, but not so reasonable if you think it is already OK and the ICP company messed up (maybe they confused your sample with someone else lol).

If you did it, I'd spread it out over at least a couple of weeks. Maybe do half or a quarter and then pause to make sure nothing seems to be going wrong.

Thanks Randy! Ill probably put only half that amount in lol. That would only raise it by 3 ppt. 5 kg of sodium chloride is a lot! Scary! So 2.5kgs feels better lol.

I asked if it was possible they messed up my sample with someone elses and they said no we put coding into the samples lol. I asked if they would do a retest. Well see what they say.

Whats the red seas Salinity? I found that 40ppt is the average salinity of the red sea and most of the coral reef is on the shoreline. And 10% of the species living in the Red sea live only in the Red sea and nowwhere else in the world. Cool. I hope atlantic species can tolerate higher salinity! I agree over a few weeks is a good idea.

When i can afford another test, off to Triton next time.

Fwiw i read it can be -57c 30000 feet above. I wonder how a sample of tank water would be in that temperature.

 

[Cory]

I remeber when filling the tank woth seachems vibrant sea. The water was very foggy. After it it cleared up there was a dusting over the glass.