Use calibration fluid they said!

[Koh23]

Well, on all salinity calibration solutions that i saw, few things are crucial:

Shake well before use, discard first few drops, clean well dropper, and discard whole solution if open for longer period of time....

Even in bottle, there is evaporation, there is buildup, so.....

Not worth, buy once, use to verify readings vs rodi water, make note of difference (if any), discard.... And use rodi....

 

[Randy Holmes-Farley]

Screenshot from article randy posted in post 32 above, red sea keep saying there's is designed for seawater and keep mentioning " sea water " and " nsw" so does this mean If test true natural sea water " nsw" at 25° then its fine to use, but what about testing "asw" which I use and alot of other reefers use artificial sea water " asw" so @Randy Holmes-Farley are they saying its only accurate to use " nsw" ,just curious is all on your thoughts

The small differences between artificial seawater and natural seawater are not generally significant in terms of salinity measurement by refractometer or conductivity. Magnesium being elevated and changes in the chloride to sulfate ratio are the biggest impacts in this regard, but the effects are small.

 

[Randy Holmes-Farley]

Well, on all salinity calibration solutions that i saw, few things are crucial:

Shake well before use, discard first few drops, clean well dropper, and discard whole solution if open for longer period of time....

Even in bottle, there is evaporation, there is buildup, so.....

Not worth, buy once, use to verify readings vs rodi water, make note of difference (if any), discard.... And use rodi....

The only rationale for shaking is if there are drops of fresh water condensation inside the bottle that have become unmixed from the seawater. In general, seawater cannot ever separate.

 

[Koh23]

Yes, but, it can evaporate, and then solution is no longer 35ppt, so, really no use, if stays open longer period of time.

At least, thats how i figure....

 

[EeyoreIsMySpiritAnimal]

Yes, but, it can evaporate, and then solution is no longer 35ppt, so, really no use, if stays open longer period of time.

At least, thats how i figure....

This explanation doesn't explain shaking the bottle...

I shake stuff out of habit/muscle memory from using the API nitrate test when I first started

 

[Randy Holmes-Farley]

Yes, but, it can evaporate, and then solution is no longer 35ppt, so, really no use, if stays open longer period of time.

At least, thats how i figure....

Possible, but unless you leave it open for extended periods, evaporation is not a concern.

 

[TheyGaveItToMe]

The only rationale for shaking is if there are drops of fresh water condensation inside the bottle that have become unmixed from the seawater. In general, seawater cannot ever separate.

It is the first step in the direction, which is good enough rationale for anyone with common sense.

 

[snorklr]

its been a long week and i'm exhausted...just read through randy's article and it makes my brain hurt...no wonder people just want to order something off amazon that works

 

[Brucealmighty]

Surely if you get 35 grams of sea salt add it to one litre (1000ml) of rodi water and you have a perfect mix to calibrate your refractometer????

Ps edit and yes presuming your house water and sea salt are all at a nice temperature of 25c as best as possible not being cheeky or anything is something I accidentally found and just seems stupidly logical if those 2 words can be used consequentially?

 

[DanTheReefer]

I switched back to the old school swing arm hydrometer for this reason, if you keep it clean and use properly the measurements will be precise to the amount we require

 

[Sshannon]

These guys explain it better than I can why its best to calibrate with saltwater.

 

[Necrodaemus]

I realize this thread is 6 months old but felt the need to chime in regarding Fritz 35ppt fluid. Stay away from it, simply put. I wanted to calibrate my 2 refractometers after calibrating to 0 with RODI and distilled so I picked up a bottle of Fritz from the LFS. They had just got the bottles in that day (I called the week prior asking if they had any and the employee placed the order while we were on the phone). When I got home to calibrate with it, I noticed that fluid started coming out when I was shaking the bottle. The cap was on tightly and the twist tip was also tightened down. It was surprising to see that there wasn’t a seal under the cap to prevent this.
Both refractometers showed it as 40ppt. I called Fritz and spoke to a customer service rep and after providing her the batch number, she stated that they have been having issues with batches lately and that they are looking into new packaging options. She then stated that she didn’t feel comfortable with sending a replacement as it would likely put me in the same situation and advised to return to the store and that she was going to have their sales rep contact the store to have the bottles pulled (they are still on the shelves a couple weeks later, btw ).
I have since ordered a bottle of BRS/Brightwell 35ppt solution and it’s spot on 35 across 2 refracts and a Hanna checker.

 

[Randy Holmes-Farley]

It is the first step in the direction, which is good enough rationale for anyone with common sense.

Lots of manufacturers do not understand their own products.

 

[Randy Holmes-Farley]

Surely if you get 35 grams of sea salt add it to one litre (1000ml) of rodi water and you have a perfect mix to calibrate your refractometer????

Ps edit and yes presuming your house water and sea salt are all at a nice temperature of 25c as best as possible not being cheeky or anything is something I accidentally found and just seems stupidly logical if those 2 words can be used consequentially?

No. it is neither logical nor accurate. That will fail because a substantial amount of the 35 g is moisture.

 

[Brucealmighty]

No. it is neither logical nor accurate. That will fail because a substantial amount of the 35 g is moisture.

I can't say I have much moisture in my salt because I wouldn't be able to pour it out and it would clump together, but I will bow down to your greater expertise with the matter, thank you for putting me right, oh ps edit I use the tropic marine pharmaceutical grade sea salt if that would make a difference?

 

[Randy Holmes-Farley]

I can't say I have much moisture in my salt because I wouldn't be able to pour it out and it would clump together, but I will bow down to your greater expertise with the matter, thank you for putting me right, oh ps edit I use the tropic marine pharmaceutical grade sea salt if that would make a difference?

There is a lot in the solid magnesium and calcium salts typically used. Solid “dry” Magnesium sulfate heptahydrate is 50% water by weight, for example.

 

[Brucealmighty]

There is a lot in the solid magnesium and calcium salts typically used. Solid “dry” Magnesium sulfate heptahydrate is 50% water by weight, for example.

Cool thanks for the information, and I honestly didn't know that, but is good to know, I have to go to the shop now for a bottle of calibration fluid, it's what I will be telling the lady of the house anyway

 

[Hellic]

I got some fritz calibration solution months ago actually. Saved my tank. I was using rodi to calibrate my refractometer but every coral I put in my tank kept dying except mushroom corals because well, they can survive a nuke. Lol. Finally i broke down got an ICP test and found my salinity was .003SG off. Instead of 1.026SG I was at 1.023! purchased some fritz on amazon and had a leaky package also so I just poured the water in the package back into the fritz bottle. Sure enough fritz was showing my refractometer was .003SG off. I haven't had an issue with corals dying since. Literally saved my reefing career. But I definitely think using Randy's method as a redundancy or primary would be a great option to ensure your solutions are still correct.

 

[TheyGaveItToMe]

Lots of manufacturers do not understand their own products.

It must be frustrating always being the smartest person in the room.

 

[capted]

I got some fritz calibration solution months ago actually. Saved my tank. I was using rodi to calibrate my refractometer but every coral I put in my tank kept dying except mushroom corals because well, they can survive a nuke. Lol. Finally i broke down got an ICP test and found my salinity was .003SG off. Instead of 1.026SG I was at 1.023! purchased some fritz on amazon and had a leaky package also so I just poured the water in the package back into the fritz bottle. Sure enough fritz was showing my refractometer was .003SG off. I haven't had an issue with corals dying since. Literally saved my reefing career. But I definitely think using Randy's method as a redundancy or primary would be a great option to ensure your solutions are still correct.

Yes. I use his mix to double check. Works great!!