Should i trust calibration fluid or rodi?

[Jake_the_reefer]

I just got a new refractometer and I'm getting odd results I calibrated it to 35 like the fluid suggests but when I test rodi water I get about -5.
Should i trust calibration to rodi or AcuraSea calibration fluid.

 

[brad shawn]

I’m sure you thought of this already but maybe try another calibration fluid? Compare the results... or buy a jug of distilled water and compare all 3 results ? Pretty lame answer I know lol

 

[Jake_the_reefer]

I’m sure you thought of this already but maybe try another calibration fluid? Compare the results... or buy a jug of distilled water and compare all 3 results ? Pretty lame answer I know lol

My lfs only has the one solution lol. But I do have distilled water in my fridge I can use.

 

[mfinn]

I just got a new refractometer and I'm getting odd results I calibrated it to 35 like the fluid suggests but when I test rodi water I get about -5.
Should i trust calibration to rodi or AcuraSea calibration fluid.

What does the manufacturer say?
That's what you should go by.

 

[kswan]

Trust the calibration fluid. The RODI is too far from your desired range to use for calibration.

 

[Jake_the_reefer]

So I tested my distilled water and it had same results as the rodi. My tanks waters read the same as well and were under 1.025 about the same amount that the rodi was under 0

 

[Jake_the_reefer]

Just read manufacturer instructions.. use rodi or tap.

 

[homer1475]

Trust the calibration fluid. The RODI is too far from your desired range to use for calibration.

Exactly this.

I'm sure as most, the manufacturer suggests calibrating with Ro/DI or distilled. The problem lies with how far up that scale from 0 you are reading to, as opposed to closer to the scale we read from. There is a whole article I read somewhere with curves of how far out of calibration a unit can be when calibrating to 0.

Either trust the calibration fluid, or buy another brand and compare. But you should always calibrate closer to the section of the scale your going to take a reading from(in our case 1.025).

EDIT:
I think it was an older article that @Randy Holmes-Farley wrote, but I could be wrong.

 

[Jake_the_reefer]

Exactly this.

I'm sure as most, the manufacturer suggests calibrating with Ro/DI or distilled. The problem lies with how far up that scale from 0 you are reading to, as opposed to closer to the scale we read from. There is a whole article I read somewhere with curves of how far out of calibration a unit can be when calibrating to 0.

Either trust the calibration fluid, or buy another brand and compare. But you should always calibrate closer to the section of the scale your going to take a reading from(in our case 1.025).

Makes sense thank you

 

[Jake_the_reefer]

I take hydrometer as a grain of salt but... when calibrated to the solution the refractometer and the hydrometer produce the same exact result for my two tanks. I think I'm taking the calibration fluid

 

[mfinn]

Just read manufacturer instructions.. use rodi or tap.

That seems surprising until I read Homer1475's response.
The last 2 refractometers I bought came with calibration fluid.

 

[Retro Reefer]

Go with the calibration fluid, get your LFS to verify or make a redundant solution of your own to double check.. 1.55 grams iodized salt mixed with 40.25 grams of distilled water makes 1.026 solution.

 

[Turnage]

Trust the calibration fluid. Refractometers can be only calibrated to a single point. The calibration fluid is 1.026, the salinity you're trying to achieve is 1.026 (around there) so therefore you calibrate to 1.026. check the calibration fluid bottle. There should be an expiration date. As long as you're within the calibration interval date the bottle is still good.

 

[Jake_the_reefer]

Trust the calibration fluid. Refractometers can be only calibrated to a single point. The calibration fluid is 1.026, the salinity you're trying to achieve is 1.026 (around there) so therefore you calibrate to 1.026. check the calibration fluid bottle. There should be an expiration date. As long as you're within the calibration interval date the bottle is still good.

It doesnt have an exp date it just states "our mixture can last for months or even years if not exposed to foreign substances or left open"

 

[Turnage]

 

[jsvand5]

I have a couple different calibration solutions now after an incorrect solution caused me to lose a good amount of acros. My salinity was actually at 1.031and the solution said 1.026. It was the one thing that didn’t occur to me as a possible problem when my SPS were declining.

 

[Loggerhead]

I had a bottle of calibration fluid go bad and my tank suffered for it. Take your solution to the store and have them test it on their refractometer. Order another bottle online and compare, they’re between $5-$10 and any livestock you lose will run you more than that, plus it is $5 for the extra piece of mind.
I lucked out and found that my refractometer reads dead on 0 with RO/DI when it is properly calibrated with calibration fluid. It’s somewhat unusual for it to be dead on 0 but has been checked at 3 LFS with tank water, their calibration solutions and their RO/DI in addition to mine.

 

[EMeyer]

Calibrating with RODI is incorrect. Use 35 ppt calibration fluid.

Everyone always brings up manufacturers instructions. Manufacturer's instructions are written by some random person at the company. It's not like they've got a processional chemist and science writer on staff doing this stuff. Its probably just the guy at the factory who speaks the best English. Like a bunch of frat guys piling into the car after a night of drinking, that picks the least drunk one to be the driver.

Snark aside, I will add that evaporation makes these standards go bad surprisingly quick if left open. I make my own standard solutions, and regularly forget to close them. They often deviate by 2 ppt by the time I realize theyre left open.

I think the best thing we can do is make 35 ppt standards regularly with a quality scale, and always keep two on hand.

 

[jason2459]

Does your calibration solution need calibrated?

One of the very basic parameters that we need to maintain is that of salinity which can directly and indirectly effect all other parameters. http://reef2reef.com/threads/optimal-parameters-for-a-coral-reef-aquarium-by-randy-holmes-farley.173563/ Being able to accurately test for and read what...

www.reef2reef.com

 

[jurgenph]

to add more fuel to the fire, make sure to use a calibration fluid that is made for a refractometer, not a conductivity probe.
as it will read different.


J.