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Check your refractometers!!


nsousa

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I purchased a brand new red sea refractometer when i purchased my salt mix.   I noticed when mixing my aquaforest reef salt into a 5 gallon bucket i was using quite a bit more salt than the instructions said but i always figured the refractometer being was correct.  

Well it wasnt i read the instructions on calibrating the refractometer and its was off by almost 5ppm.  Now i have to substitute salt water with rodi water in my tank that is cycling.   

I hope doesnt affect the anything i really want my salinity at 35ppm.

 

Lesson learned new or old check your calibration!!

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Good reminder - and it likely won't have any impact in particular to your cycling tank so you should be fine.

 

I use a hydrometer (quality one) so I don't really mess with calibrating more than the one time I compared it to a properly calibrated refractometer... 

 

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I started by calibrating with the distilled water that came with mine.

 

I then went with calibration fluid. It was a tiny bit off.

 

I now calibrate every 2 weeks with both fluids.

 

Mine stays pretty much right on the mark but I still calibrate it regularly 

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I calibrate mine from time to time. For some, you also need to re-calibrate when there have been large changes in ambient temperature. A 10 degree Fahrenheit change can give you a 1-1.5ppm negative error if left uncalibrated. ATC can only compensate for a few degrees of difference. 

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Sailingeric

I have one for home beer brewing and once it was calibrated it has held but it also temp compensates and cost almost $80.  The one for my SW tank I do a drop or two of calibration fluid every time I use it but the temps in my house where I store are fairly constant so it hardly ever needs tweeking but I also paid less than $30 for and I dont think it temp compensates or if it does it is slower in doing so. 

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5 minutes ago, Sailingeric said:

I have one for home beer brewing and once it was calibrated it has held but it also temp compensates and cost almost $80.  The one for my SW tank I do a drop or two of calibration fluid every time I use it but the temps in my house where I store are fairly constant so it hardly ever needs tweeking but I also paid less than $30 for and I dont think it temp compensates or if it does it is slower in doing so. 

IIRC you can bust out some math to compensate for temp but I never worry about it. I do need to check mine against my homebrew  hydrometer sometime though.

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Sailingeric
1 hour ago, Nocturnal said:

IIRC you can bust out some math to compensate for temp but I never worry about it. I do need to check mine against my homebrew  hydrometer sometime though.

The SG will be different due to the way the light bends for wort vs salt water.  I have done SW on the beer one, next time I brew will do wort on the SW one to see the difference. 

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1 minute ago, Sailingeric said:

The SG will be different due to the way the light bends for wort vs salt water.  I have done SW on the beer one, next time I brew will do wort on the SW one to see the difference. 

I've definitely noticed that. From what I can tell my actual hydrometer I use (mostly for wine as I don't worry about beer SG tbh) seems to be pretty accurate.

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3 hours ago, MrJoel said:

I calibrate mine from time to time. For some, you also need to re-calibrate when there have been large changes in ambient temperature. A 10 degree Fahrenheit change can give you a 1-1.5ppm negative error if left uncalibrated. ATC can only compensate for a few degrees of difference. 

Very true. Some models require certain temps for accurate reading, some read with a  wide range of temps.

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I also urge people to be very cautious while calibrating.  Miscalibration is a real and a bad thing for your reef!!  And your sanity.  Keep reading for my personal experience.

 

As per the instructions of my Vertex and Sybon salinity refracs, I decided I would calibrate them last summer.  Instructions, and almost every person I had talked to, said to calibrate to 0 with RODI.  K, did that, and felt pretty good about my newly calibrated refracs and getting back on track in case they were off.

 

Welp.  Come a few months later, say November-December, I'm sure I was days away from a tank crash.  Terrible algae (diatoms/cyano?) my sexy shrimp died, emerald crab died, cleaner shrimp and then hermit... all within a month.  Huh, weird.  The fish were fine, and almost all corals were also fine!  Except... the zoas were dying off.  I had a sweet Sunny D colony (grown from 1 polyp to 30 or more in a few months), Rainbow Hornets, pink and green varieties of Dragon Eyes, and several others.  I was starting and progressing with a zoa garden.  I lost all but my green palys, the pink Dragon Eyes and, miraculously, some random zoa polyps I thought were gone started popping back up, seemingly from the dead.  They are still trying to color back up.  It's so so so cool that they came back.

 

Anyway, I thought I had allelopathy, or nutrient issues, or low alk issues, too much or not enough light... you name it.  I ordered a 4-stage RODI unit, skimmer, some 2-part, iodine and Revive for dips, some ROX carbon test kits... Eventually, while giving away my dying zoas, I asked someone to test my salinity as a last-ditch effort.  I was in a slump and the tank looked bad.  I always kept my tank at 36ppt.  Want to know what they read my salinity as?? ...27ppt!  Yes, you read that right: 27 ppt !!!!!!

 

YIKES.

 

Checked against an Apex conductivity reading... 28ppt.

 

OMG. 

 

I was calibrating with RODI to 0.  Like the instructions said, and like everyone else told me to.  I wasn't off by 1, 2 or even 5ppt. This was way bad.

 

Anyway, I immediately ordered 3 different 35ppt calibration standards and made the DIY calibration fluid from ReefKeeping.  I can say with certainty that WE ARE NOW AT 35ppt, no question about it!  Could there still be a 1-2ppt variation?  Maybe, but my local fish dude confirms as well as Apex, and the 4 calibration standards are right on point.

 

When I check against RODI now... it reads off the scale, and about -0.5ppt or so.

 

I see some people share their experiences using RODI successfully, and that's awesome.  It must depend on a lot of things... temperature, model of the refract. 

 

I reached out to Vertex and they recommended following the instructions, but if I "had better success with calibration fluid, then keep doing that." Lol. So, I'm doing that!

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squamptonbc
4 hours ago, nsousa said:

Any thoughts on the milwaukee digital refractometer?? 

 

Ive got one. It works okay but honestly its not a great time saver or anything.

 

I got it as with getting older its getting hard to read a regular refractometer.

 

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I just picked up my calibration solution. 35ppm.  The zero tds calibration from red sea as per instructions was not of by much from calibration fluid.    

 

Ill be using calibration fluid as my reference but still extremly disappointed the a new refractometer

Was off by 5ppm, thats ridicoulous

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16 hours ago, sugar said:

I also urge people to be very cautious while calibrating.  Miscalibration is a real and a bad thing for your reef!!  And your sanity.  Keep reading for my personal experience.

 

As per the instructions of my Vertex and Sybon salinity refracs, I decided I would calibrate them last summer.  Instructions, and almost every person I had talked to, said to calibrate to 0 with RODI.  K, did that, and felt pretty good about my newly calibrated refracs and getting back on track in case they were off.

 

Welp.  Come a few months later, say November-December, I'm sure I was days away from a tank crash.  Terrible algae (diatoms/cyano?) my sexy shrimp died, emerald crab died, cleaner shrimp and then hermit... all within a month.  Huh, weird.  The fish were fine, and almost all corals were also fine!  Except... the zoas were dying off.  I had a sweet Sunny D colony (grown from 1 polyp to 30 or more in a few months), Rainbow Hornets, pink and green varieties of Dragon Eyes, and several others.  I was starting and progressing with a zoa garden.  I lost all but my green palys, the pink Dragon Eyes and, miraculously, some random zoa polyps I thought were gone started popping back up, seemingly from the dead.  They are still trying to color back up.  It's so so so cool that they came back.

 

Anyway, I thought I had allelopathy, or nutrient issues, or low alk issues, too much or not enough light... you name it.  I ordered a 4-stage RODI unit, skimmer, some 2-part, iodine and Revive for dips, some ROX carbon test kits... Eventually, while giving away my dying zoas, I asked someone to test my salinity as a last-ditch effort.  I was in a slump and the tank looked bad.  I always kept my tank at 36ppt.  Want to know what they read my salinity as?? ...27ppt!  Yes, you read that right: 27 ppt !!!!!!

 

YIKES.

 

Checked against an Apex conductivity reading... 28ppt.

 

OMG. 

 

I was calibrating with RODI to 0.  Like the instructions said, and like everyone else told me to.  I wasn't off by 1, 2 or even 5ppt. This was way bad.

 

Anyway, I immediately ordered 3 different 35ppt calibration standards and made the DIY calibration fluid from ReefKeeping.  I can say with certainty that WE ARE NOW AT 35ppt, no question about it!  Could there still be a 1-2ppt variation?  Maybe, but my local fish dude confirms as well as Apex, and the 4 calibration standards are right on point.

 

When I check against RODI now... it reads off the scale, and about -0.5ppt or so.

 

I see some people share their experiences using RODI successfully, and that's awesome.  It must depend on a lot of things... temperature, model of the refract. 

 

I reached out to Vertex and they recommended following the instructions, but if I "had better success with calibration fluid, then keep doing that." Lol. So, I'm doing that!

My sybon came with distilled water to be calibrated to 0.

 

I then tested with 35ppt cal fluid.

 

Mine was off slightly.

 

I prefer the 35ppt cal solution too.

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I calibrate mine with 35 ppt calibration every time. Not sure if it was just mine but after about 3 months the calibration fluid was off by 2 ppt. I always closed it tightly after every use. The only reason i even noticed was i got a new bottle free on a order i placed and decided to check it.

 

Needless to say i now have a Milwaukee 887 and it showed the original calibration fluid at 37ppt and the new at 35 ppt

 

 

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6 hours ago, jjam said:

I calibrate mine with 35 ppt calibration every time. Not sure if it was just mine but after about 3 months the calibration fluid was off by 2 ppt. I always closed it tightly after every use. The only reason i even noticed was i got a new bottle free on a order i placed and decided to check it.

 

 

4

I keep mine tightly closed and inside a ziplock bag with the air mostly squeezed out because I am paranoid about the fluid somehow evaporating. And you calibration is only as good as the calibration fluid. =P

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It's a great point, most people have to learn this the hard way. When I was using a standard Refractometer I calibrated monthly, now that I use a digital one I calibrate every time :) I had a bad experience too.

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Just thought i would chime in again. Im completely fed up with the Red Sea Refractometer i got.   Ive only had for a few weeks and its a complete piece of crap. I purchased a BRS refractometer with 3 different calibration fluids. All check in at 34-35ppt.  My RS refractometer must have a defect because it keeps losing its calibration with in minutes of testing water.   Considering what it cost and my experience with it iwould never recommend it.   Im actually a fan of red sea products but after my experience and other reviews online they really dropped the ball with this thing.   Likely going to order a milwaukee 877 digital 

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Indiana Reefin

I calibrate mine with calibration fluid before each use. This is crucial because all it takes to throw a refractometer off is if you set it down on a table. I would say 1 our every 4 times I have to adjust the refractometer. I am OCD though. 

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30 minutes ago, Indiana Reefin said:

I calibrate mine with calibration fluid before each use. This is crucial because all it takes to throw a refractometer off is if you set it down on a table. I would say 1 our every 4 times I have to adjust the refractometer. I am OCD though. 

Yes even calibrating everytime it doesnt work right for me.   I do mind calibrating  everytime but it just doesnt work.   Heres an example.

1-Ill calibrate it using 35ppt solution

2-ill test my tank water which i know is 35ppt and it shows less.  

3- ill then use the calibratiom fluid and its off again.   

That cant be right. Im not talking being off by 1ppt any where from 2-4.   Thats way to much for me or anyone.

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1 hour ago, nsousa said:

Yes even calibrating everytime it doesnt work right for me.   I do mind calibrating  everytime but it just doesnt work.   Heres an example.

1-Ill calibrate it using 35ppt solution

2-ill test my tank water which i know is 35ppt and it shows less.  

3- ill then use the calibratiom fluid and its off again.   

That cant be right. Im not talking being off by 1ppt any where from 2-4.   Thats way to much for me or anyone.

 

sounds like something is broken. Maybe you should give a call in to red sea and see what they can do for you. Chances are they will either repair, replace, or give you a discount on a new one.

 

1 hour ago, Indiana Reefin said:

Sounds like your refractometer is bad 

 

id say so aswell

 

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