salinity calibration

[burning2nd]

So after all these years of never checking anything.. my best friend said 2 me last night "when was the last time you used this" (my refractometer). I replyed a long time ago... and proceeded to check my salt level out..


mind after a year+ of water changes my level was only down to 1.023. I use to run closer to 30 but i do remember saying to my self that i wanted to lower the salt level cause its more cost effective,

anyway so i cross checked with my other refratometer and i found that both of them have a diffrent reading after all these years they must have changed a lil...

so this is the questtion.. what does this mean

"PINPOINT Salinity Montior 53.0mS Calibration Fluid +/- 1%@ 77degree F."

the 53.0 is what i dont get.. whats that in converted to PPT?

 

[dragoneggs]

Millisiemens... it is a measure (unit) of electrical conductivity.

 

[burning2nd]

ah 1.026 cool... thanks

 

[Holygral]

Pick up some calibration fluid and give yourself some piece of mind, pinpoint sells it, there is a high and low fluid to calibrate with.

 

[jrgilles]

I just chatted with barrier reef about this. What they do is set the refractometer with a calibration fluid. Then once its set, they test DI water (which should be 1.000) and make sure it reads correctly.

rob

 

[Kurt_Nelson]

That's not right... unless of course you want to check water to make sure its 1.000. Not arguing what you were told - just that you shouldn't do it that way.

Use the calibration fluid and set it at that - that's the range you're measuring. For example, when my refractometer is spot on with the Pinpoint fluid, it does NOT read zero with DI water.

There is a recent thread about all this in the Chemistry forum also.

 

[burning2nd]

wait a min... here were not making any sence..

i have the pinpoint cali fluid.. what should that read?
53 mS is what in parts per trillion 1.026?

 

[braddo]

wait a min... here were not making any sence..

i have the pinpoint cali fluid.. what should that read?
53 mS is what in parts per trillion 1.026?

53.0ms = 35.00ppt = 1.0259sg
http://www.americanmarineusa.com/salinityconversion.html

 

[jrgilles]

thanks for the correction kurt. That makes sense that you just calibrate it for a specific range.

 

[barrierreefcf]

That's not right... unless of course you want to check water to make sure its 1.000. Not arguing what you were told - just that you shouldn't do it that way.

Use the calibration fluid and set it at that - that's the range you're measuring. For example, when my refractometer is spot on with the Pinpoint fluid, it does NOT read zero with DI water.

There is a recent thread about all this in the Chemistry forum also.[/QUOTE

Kurt is right. Wont always be right at 1.000. Some Refracts we have had did but others have a trace measurement. I'll have to read the Chemistry Thread to find out what its supposed to measure.

 

[barrierreefcf]

Got it now. Kurts point is correct but theoretically if your refractometer had zero slope error you should get a 1.000 reading of RO/DI water after calibrating with Pinpoint's Solution. For measuring our tank's salinity range using the solution is best and double checking with RO/DI is meaningless, other than checking your unit for slope error.

 

[Kurt_Nelson]

Agree... with a perfect unit with no slope error, it wouldn't matter where you calibrate it. Now if I'm using it to check the SG of my homebrew... that's a totally different calibration fluid!

 

[jrgilles]

Do you use the same refractometer for checking the O.G. of your homebrew? I saw some that were specifically marketed for homebrew, are they different?

Would be nice to be able to use this for getting O.G., especially if it will do a temp adjustment for me. Would be so much more accurate.

If I could use this to do OG and FG, it would really cut down on the amount of wort I had to use for testing (although I do enjoy drinking some of it out of the hydrometer cylinder.)

 

[Kurt_Nelson]

[minor thread drift...]

Actually... it was more of a joke than being serious! I think the ones marketed to homebrewers just have different scales on them (Brix, potential alcohol) along with the SG. As far as I know, SG is SG... regardless of the fluid being measured.

I've used my refractometer a few times to test wort, and its been within a couple points of my hydrometer. But I still use the hydrometer because, well... it's what I've always used, and consistency is half the battle. I don't really want to change things up once I have something that works. Plus... my hydrometer cylinder isn't much bigger than the hydrometer so I'm not wasting much, and like you say - taking a sip or two at that stage is just part of the process!

[/minor thread drift. ]