Lesson learned about using R/O for refractometer calibration

[Russ265]

So what should I do, buy a new refractometer? I calibrate with solution at 35ppt and when I do it with RODI I get a negative number.

roll with your "calibrated" number for a spell. but realize you have something i wouldnt trust beyond the directions on the back of a salt bag that states "x cups per gallon".

it WILL go out of whack further.

if you are cool with that then go with it. but blaming your ebay blessed refractometer with your salinity woes is wrong.

 

[jason2459]

So what should I do, buy a new refractometer? I calibrate with solution at 35ppt and when I do it with RODI I get a negative number.

You're fine. Calibrate with the 35ppt standard and it will be where you want it. Don't let him bully you.

 

[Russ265]

You're fine. Calibrate with the 35ppt standard and it will be where you want it. Don't let him bully you.

so. because his calibration is already out of whack. he should continue trusting it for years down the line?

that calibration screw is just for looks

lol none of you are justifying this trashed refractometer that would make me comfortable as r2r advice.

id expect a ton more from you guys.

i run tap water in my wife's 40 gallon to keep softies. id never advocate it was "fine" for everyone.

 

[jason2459]

To the OP its been brought up several times but well worth posting again. It explains most everything necessary to using and calibrating a refractometer.

Refractometers and Salinity Measurement by Randy Holmes-Farley
http://reefkeeping.com/issues/2006-12/rhf/

 

[Russ265]

To the OP its been brought up several times but well worth posting again. It explains most everything necessary to using and calibrating a refractometer.

Refractometers and Salinity Measurement by Randy Holmes-Farley
http://reefkeeping.com/issues/2006-12/rhf/

no offense to that post. but you are doing nothing other than remarking/calibrating your device to offset it's terrible design.

there is no difference to this than using a hydrometer and marking the "sweet spot"

im sure the intent was meant to avoid aquarist's from making tragic mistakes but it still bandaids the underlying problem. your refractometer is so wrong you need to refractively mark the correct spot.

 

[jason2459]

no offense to that post. but you are doing nothing other than remarking/calibrating your device to offset it's terrible design.

there is no difference to this than using a hydrometer and marking the "sweet spot"

im sure the intent was meant to avoid aquarist's from making tragic mistakes but it still bandaids the underlying problem. your refractometer is so wrong you need to refractively mark the correct spot.

Have you read my posts? Or do you just want to argue.

 

[Russ265]

Have you read my posts? Or do you just want to argue.

go halfway down about the slope.

Can such a refractometer be used? Yes, but only if it is calibrated using a solution known to have a refractive index close to that of the samples to be tested. Calibrating using a liquid matching seawater, for example, can lead to a slope correction as shown in Figure 14. In this type of calibration, the refractometer is accurate at that refractive index, but not necessarily at other values.

he is getting other than 0 with ro.

please. read the whole article and how it applies. like i said. correct, but a bandaid.

 

[jason2459]

go halfway down about the slope.

Can such a refractometer be used? Yes, but only if it is calibrated using a solution known to have a refractive index close to that of the samples to be tested. Calibrating using a liquid matching seawater, for example, can lead to a slope correction as shown in Figure 14. In this type of calibration, the refractometer is accurate at that refractive index, but not necessarily at other values.

he is getting other than 0 with ro

That wont mater if he keeps it calibrated to a known standard at the salinity he is trying to achieve.

 

[Russ265]

That wont mater if he keeps it calibrated to a known standard at the salinity he is trying to achieve.

key word: "keeps his junk measurement device" calibrated.

like i said. no different than marking a sweet spot on a hydrometer

your advice: keep it blessed with 1.026 calibration fluid and nothing will go wrong.

 

[jason2459]

key word: "keeps his junk measurement device" calibrated.

like i said. no different than marking a sweet spot on a hydrometer

Minus the other issues with swing arm hydrometers. But they can be used just fine. PaulB has used one for years. Strike that, decades.

I've already stated the refractometers I would recommend. But a cheap $30 refractometer will do. In fact the el cheapo brine refractometers I've used in the past (at least 3 different ones) have held their calibration better then the red sea one.

 

[Russ265]

Minus the other issues with swing arm hydrometers.

I've already stated the refractometers I would recommend. But a cheap $30 refractometer will do. In fact the el cheapo brine refractometers I've used in the past (at least 3 different ones) have held their calibration better then the red sea one.

what a coincidence!!!!!!!!

hmmmm alibaba, ebay, or.....
idk what you buy, but i will state my red sea refractometer is right on everytime.

btw my well-researched ebay unit is the same as the red sea unit. the rust on the swing pin is why i went with another.

 

[jason2459]

what a coincidence!!!!!!!!

hmmmm alibaba, ebay, or.....
idk what you buy, but i will state my red sea refractometer is right on everytime.

Thats good. I guess I'm done with this "conversation" since you don't care to read my posts and just trying to argue.

 

[Russ265]

Thats good. I guess I'm done with this "conversation" since you don't care to read my posts and just trying to argue.

i heard you think red sea is a dollar tree product despite it's amazing reviews.

i heard you advocate using cheap units without people doing their research. maybe any old beer refractometer will do?

ive taken every assumption you had and thrown it back at you. not out of spite mind you, but because i hate misinformation.

keep using dollar tree refractometers and calibrating them to the fluid while your ro reads -20.

but dont give me that baloney about me not reading your intent.

 

[jason2459]

To the OP I would again recommend reading the links in these two posts.

No, it wont work using the measurements he gave in the article.


https://www.reef2reef.com/threads/does-your-calibration-solution-need-calibrated.250133/

And for those that are saying to calibrate to 0 with freshwater that will only be viable for a true seawater refractometer which most sold to hobbyist are not. Veegee, Vitalsine, D&D H2Ocean, Red Sea, and Milwaukee digital have true seawater refractometers that could be calibrated to 0 with freshwater. Of those I can not recommend the Red Sea one. I have had and have used each of them. My favorite is the veegee/vitalsine (rebranded veegee). I would still reference a 35ppt solution for accuracy and correct mechanics.

To the OP its been brought up several times but well worth posting again. It explains most everything necessary to using and calibrating a refractometer.

Refractometers and Salinity Measurement by Randy Holmes-Farley
http://reefkeeping.com/issues/2006-12/rhf/

 

[Russ265]

To the OP I would again recommend reading the links in these two posts.

this guy doesnt read at all.

op stated he was calibrating with rodi water and was off at 1.026.

you are doing nothing for the op except quoting someone else's work.

i doubt you know what you are even advocating and it's pitfalls and bad practices.

 

[bobman]

i knew it. you guys are buying alibaba equipment and blessing it with 1.026 fluid and wonder why it doesnt work like a proper refractometer....

my 0 stays 0 and my 1.026 is still 1.026

youre better off buying a hydrometer and marking it with nail polish at the fish store. using calibration fluid to fix your issue is defeating the entire purpose.

if you "calibrated" with 1.026 and ro is other than 0, you have junk at the end of the day.

Although I do agree with Russ (MOSTLY) and use RODI to calibrate mine and if I used a solution and then used rodi if it did not read 0 then I would scrap it and buy a new one. I must point out most refractometer for the reef tank are not designed to reed 0 or an sg of 1.0000 and it clearly states that right on the box of that red sea refractometer

 

[Russ265]

Although I do agree with Russ (MOSTLY) and use RODI to calibrate mine and if I used a solution and then used rodi if it did not read 0 then I would scrap it and buy a new one. I must point out most refractometer for the reef tank are not designed to reed 0 or an sg of 1.0000 and it clearly states that right on the box of that red sea refractometer

you are going more advanced now....

welcome to temperature

 

[bubbaque]

I think I am going to buy a new refractometer since they are not much money. I was looking at the Red Sea one but it does not have great reviews. They one I currently have has better reviews on Amazon.

 

[twilliard]

Here is the next best step...
Have your water tested by the Triton ICP testing and compare it to the refractometer reading

 

[Russ265]

I think I am going to buy a new refractometer since they are not much money. I was looking at the Red Sea one but it does not have great reviews. They one I currently have has better reviews on Amazon.

every single 1 star review was "it doesnt hold calibration"

that is a red flag no matter the refractometer brand.

they have more 5 star reviews than any other.
maybe a bad batch? maybe someone dropped it? idk. maybe you play hacky sack with refractometers. maybe temp.

to me. its a solid refractometer