refractometer calibration standard is off, how do we know whats real?

[Linlox]

Found my refractometer calibration standard solution was at 1.0240 instead of the 1.0264 as it should be earlier this week, which means everything was off as I had not been using my hydrometer......

Tested my freshly mixed saltwater with the Tropic Marin precision hydrometer and then used both of my refractometers to test the same freshly mixed water and they were not even close to the hydrometer.

Mixed up Randy's home brew solutions by weight for both refractometer and hydrometer testing. Hydrometer was spot on. That verified the calibration solution was off by a significant factor. Contacted the company and they are sending another bottle from a different lot#, which will get round filed. Any other industry would probably issue a recall or at least a notification for a bad lot.

So how are hobbyists, especially those that are new, supposed to be successful in this hobby when the most primary function of our care taking can be so influenced by abysmal quality control? How do we even trust tests such as PO4, Nitrate, Ammonia, Alk, Calcium, Mg etc when we cant even nail salinity? I think wide ranges are acceptable from our hobbyist tests and not reacting to any test without verification is prudent. Also why our salinity can be in a range and everything is fine, I have not started making any salinity changes to the tank and it will correct itself though water changes.

Calibration standards should be tested to X times accuracy before being shipped and include a certificate of authenticity or calibration report citing the testing methodology. If that doubled the price of our calibration solution from $8-10 to $16-20 so be it. Is this stuff just being mixed in a garage with a 15 year old uncalibrated $10 scale??? Or did the technician mixing the stuff that morning not have his coffee and forget to tare the scale?

Guess I lived in the world of NIST traceability and performed calibrations on highly sensitive instrumentation in the chemical industry for long enough to not trust and verify. (aka paranoia)

 

[BriDroid]

I ran into the same thing with a bottle of Continuum reagent Refractometer calibration solution. It was WAY off, and had caused me to run my tank with really low salinity. It wasn’t until I mixed up some of Randy’s solution that I found out. I’ll just make my own from now on!

 

[Dburr1014]

Any other industry would probably issue a recall or at least a notification for a bad lot.

That's asking a lot for hobby grade equipment, no?

 

[Linlox]

That's asking a lot for hobby grade equipment, no?

It is. But could hope.

 

[Linlox]

That's asking a lot for hobby grade equipment, no?

Although, why do they bother printing a lot # on the bottle then?

 

[Dburr1014]

Although, why do they bother printing a lot # on the bottle then?

That's a good question. IDK.

 

[threebuoys]

Found my refractometer calibration standard solution was at 1.0240 instead of the 1.0264 as it should be earlier this week, which means everything was off as I had not been using my hydrometer......

Tested my freshly mixed saltwater with the Tropic Marin precision hydrometer and then used both of my refractometers to test the same freshly mixed water and they were not even close to the hydrometer.

Mixed up Randy's home brew solutions by weight for both refractometer and hydrometer testing. Hydrometer was spot on. That verified the calibration solution was off by a significant factor. Contacted the company and they are sending another bottle from a different lot#, which will get round filed. Any other industry would probably issue a recall or at least a notification for a bad lot.

So how are hobbyists, especially those that are new, supposed to be successful in this hobby when the most primary function of our care taking can be so influenced by abysmal quality control? How do we even trust tests such as PO4, Nitrate, Ammonia, Alk, Calcium, Mg etc when we cant even nail salinity? I think wide ranges are acceptable from our hobbyist tests and not reacting to any test without verification is prudent. Also why our salinity can be in a range and everything is fine, I have not started making any salinity changes to the tank and it will correct itself though water changes.

Calibration standards should be tested to X times accuracy before being shipped and include a certificate of authenticity or calibration report citing the testing methodology. If that doubled the price of our calibration solution from $8-10 to $16-20 so be it. Is this stuff just being mixed in a garage with a 15 year old uncalibrated $10 scale??? Or did the technician mixing the stuff that morning not have his coffee and forget to tare the scale?

Guess I lived in the world of NIST traceability and performed calibrations on highly sensitive instrumentation in the chemical industry for long enough to not trust and verify. (aka paranoia)

Randy has a DIY formula to create your own calibration fluid. The formula creates salt water at the correct salinity measure for our tanks. Look at his stickies for more info.

 

[Dburr1014]

Randy has a DIY formula to create your own calibration fluid. The formula creates salt water at the correct salinity measure for our tanks. Look at his stickies for more info.

Mixed up Randy's home brew solutions by weight for both refractometer and hydrometer testing. Hydrometer was spot on. That verified the calibration solution was off by a significant factor.

Looks like he did.

 

[Randy Holmes-Farley]

Found my refractometer calibration standard solution was at 1.0240 instead of the 1.0264 as it should be earlier this week, which means everything was off as I had not been using my hydrometer......

Tested my freshly mixed saltwater with the Tropic Marin precision hydrometer and then used both of my refractometers to test the same freshly mixed water and they were not even close to the hydrometer.

Mixed up Randy's home brew solutions by weight for both refractometer and hydrometer testing. Hydrometer was spot on. That verified the calibration solution was off by a significant factor. Contacted the company and they are sending another bottle from a different lot#, which will get round filed. Any other industry would probably issue a recall or at least a notification for a bad lot.

So how are hobbyists, especially those that are new, supposed to be successful in this hobby when the most primary function of our care taking can be so influenced by abysmal quality control? How do we even trust tests such as PO4, Nitrate, Ammonia, Alk, Calcium, Mg etc when we cant even nail salinity? I think wide ranges are acceptable from our hobbyist tests and not reacting to any test without verification is prudent. Also why our salinity can be in a range and everything is fine, I have not started making any salinity changes to the tank and it will correct itself though water changes.

Calibration standards should be tested to X times accuracy before being shipped and include a certificate of authenticity or calibration report citing the testing methodology. If that doubled the price of our calibration solution from $8-10 to $16-20 so be it. Is this stuff just being mixed in a garage with a 15 year old uncalibrated $10 scale??? Or did the technician mixing the stuff that morning not have his coffee and forget to tare the scale?

Guess I lived in the world of NIST traceability and performed calibrations on highly sensitive instrumentation in the chemical industry for long enough to not trust and verify. (aka paranoia)

The solution certainly may have been off (what brand?), but all devices have their own uncertainty as well. Many do not state what that is, but those who do show a significant potential error.

For example, the Milwaukee digital refractometer MA887, for example, claims +/- 0.002 sg, so a true 1.025 could read 1.023 to 1.027.

Milwaukee MA887 Digital Salinity Refractometer

The Milwaukee Instruments digital salinity refractometer is ideal for saltwater aquarium professionals and enthusiasts.

milwaukeeinstruments.com

 

[Linlox]

The solution certainly may have been off (what brand?), but all devices have their own uncertainty as well. Many do not state what that is, but those who do show a significant potential error.

For example, the Milwaukee digital refractometer MA887, for example, claims +/- 0.002 sg, so a true 1.025 could read 1.023 to 1.027.

Milwaukee MA887 Digital Salinity Refractometer

The Milwaukee Instruments digital salinity refractometer is ideal for saltwater aquarium professionals and enthusiasts.

milwaukeeinstruments.com

Its the BRS Refracto Juice lot number EXP031428.

This is a great point and margin of error for these particular testing devices is unknown, however after calibrating to your DIY solution I have checked them against it for a few days and tested the mixed water and they are being consistant which is half our battle.

A single point calibration device is typically never very accurate as you can only set a zero and not adjust to a span, but for a salinity range we are shooting for it should be acceptable. Just starting with a accurate standard to begin with can make a +/- 0.002 drift easier to deal with. Without knowing how the standard is being tested we also do not know the error percent it may have (if our standard is being tested at production with a Milwaukee MA887 as in your instance above), thus compounding error through the testing and calibration process. This is why my calibration devices were always sent out and calibrated to 6x higher accuracy using a NIST traceable process on a schedule of usually no more then a few months, depending on the tool, to reduce this compounding effect.

One of the refractometers is a brand unknown brine type I picked up in 2009ish that has hardly ever needed adjustment (also well taken care of). The other is newer but came with a used tank and I believe is from BRS but history unknown. Hydrometer is just accurate but not convenient.

 

[Randy Holmes-Farley]

Its the BRS Refracto Juice lot number EXP031428.

This is a great point and margin of error for these particular testing devices is unknown, however after calibrating to your DIY solution I have checked them against it for a few days and tested the mixed water and they are being consistant which is half our battle.

A single point calibration device is typically never very accurate as you can only set a zero and not adjust to a span, but for a salinity range we are shooting for it should be acceptable. Just starting with a accurate standard to begin with can make a +/- 0.002 drift easier to deal with. Without knowing how the standard is being tested we also do not know the error percent it may have (if our standard is being tested at production with a Milwaukee MA887 as in your instance above), thus compounding error through the testing and calibration process. This is why my calibration devices were always sent out and calibrated to 6x higher accuracy using a NIST traceable process on a schedule of usually no more then a few months, depending on the tool, to reduce this compounding effect.

One of the refractometers is a brand unknown brine type I picked up in 2009ish that has hardly ever needed adjustment (also well taken care of). The other is newer but came with a used tank and I believe is from BRS but history unknown. Hydrometer is just accurate but not convenient.

To be honest, I do not know how they make it. I could not find it on their web site any more. I'd wildly speculate that they just try to copy the recipe I published, but that may not be true.

 

[rtparty]

Is any of it real?

 

[Linlox]

To be honest, I do not know how they make it. I could not find it on their web site any more. I'd wildly speculate that they just try to copy the recipe I published, but that may not be true.

It also says produced by Brightwell Aquatics on the bottle. Could be bought in bulk and repackaged or just label swaps. If its a repackage there could be condensation loss or other factors that effect it.

 

[BeanAnimal]

I don't bother with the calibration fluids for true calibration. I have had more "bad" batches than good.

Here are two methods you can use to stay calibrated reasonably well.

1 - using two refractometers.

- Measure with TM Hydrometer and set BOTH refractometers to match. They become the reference to each other. When they no longer read the same, then it is time to recalibrate against the TM.

2 - using one refractometer and one reference solution.

- Measure with TM Hydrometer and set refractometer to match.
- Measure your "reference standard" and record the measured value measured on the refractometer. This can be used to "calibrate" the refractometer now, but you set it to the recorded value, not the "as sold to you" value.


Hope that makes sense.

 

[Linlox]

I don't bother with the calibration fluids for true calibration. I have had more "bad" batches than good.

Here are two methods you can use to stay calibrated reasonably well.

1 - using two refractometers.

- Measure with TM Hydrometer and set BOTH refractometers to match. They become the reference to each other. When they no longer read the same, then it is time to recalibrate against the TM.

2 - using one refractometer and one reference solution.

- Measure with TM Hydrometer and set refractometer to match.
- Measure your "reference standard" and record the measured value measured on the refractometer. This can be used to "calibrate" the refractometer now, but you set it to the recorded value, not the "as sold to you" value.


Hope that makes sense.

This is exactly the plans I came up with moving forward and hopefully others see your post.

Never seemed to have this problem 15 years ago, maybe I never identified the problem and things still worked perfectly fine. Can't remember where my standard was purchased from back then.

 

[Randy Holmes-Farley]

It also says produced by Brightwell Aquatics on the bottle. Could be bought in bulk and repackaged or just label swaps. If its a repackage there could be condensation loss or other factors that effect it.

You've just got to love the Brightwell standard description at BRS. Someone doesn't seem to have much understanding of units of measure. lol

Specifications:

35 ppt @ 25°c
1.0264 ppt @ 25°c
53 µS @ 25°c


I think that should really mean:

Specifications:

35 ppt
sg = 1.0264 @ 25°c
53 mS/cm @ 25°c

Refractometer & Hydrometer Calibration Standard

Your refractometer is only as reliable as your calibration solution! Calibrating your refractometer only takes a minute and is a critical step in ensuring your tanks saltwater is mixed correctly. 1.0264sg | 35ppt | 53µS Two Sizes Available 60mL - great for refractometers 250mL - ideal for...

www.bulkreefsupply.com

 

[Linlox]

You've just got to love the Brightwell standard description at BRS. Someone doesn't seem to have much understanding of units of measure. lol

Specifications:

35 ppt @ 25°c
1.0264 ppt @ 25°c
53 µS @ 25°c


I think that should really mean:

Specifications:

35 ppt
sg = 1.0264 @ 25°c
53 mS/cm @ 25°c

Refractometer & Hydrometer Calibration Standard

Your refractometer is only as reliable as your calibration solution! Calibrating your refractometer only takes a minute and is a critical step in ensuring your tanks saltwater is mixed correctly. 1.0264sg | 35ppt | 53µS Two Sizes Available 60mL - great for refractometers 250mL - ideal for...

www.bulkreefsupply.com

LOL, wow and I bought this, completely on me for not looking closer into this.
Was just doing a quick buy of stuff:
trust BRS in the past - check
purchasing other items not specifically a cal standard - check
low cost purchase, how much time to invest in research? - check

 

[carri10]

@Linlox I am 100% with you. I used to work in a lab too and I find it really uncomfortable having to work with the level the hobby grade kits work at. (I know I could buy lab grade, but $!). The worst so far for me has been alk. We are told (as new reefers) it is one of the most important parameters to keep stable, but the kits and standards seem to have so much drift on them.
I’m following the sage advice of Randy and making up my own standards for most things these days.
Haven’t done pH yet, but I’m sure that’s next.

 

[KStatefan]

You've just got to love the Brightwell standard description at BRS. Someone doesn't seem to have much understanding of units of measure. lol

They do not look at their mixing instruction for their salt

"134 g per 1 US-gallon (3.785 L) of purified water yields a specific gravity of ~1.025 g/cm3, with a pH of ~8.30 and alkalinity of ~7.5 dKH."

 

[taricha]

if you have purported standards that give inconsistent results, and you want to evaluate the standards - you need to measure based on the fundamentals.
So you can use Randy's DIY standards article...
https://www.reef2reef.com/ams/reef-aquarium-salinity-diy-calibration-standards.956/
or something like this device for S.G. that I played with.
https://www.reef2reef.com/threads/p...r-measuring-density-specific-gravity.1066348/