Refractometer adjustment question or problem?

[77pm77]

Hello I just recieved my new refractometer and I can't seem to get it to stay calibrated. I have the calibration fluid but it just does not stay the same day after day. I have been recalibrating it each day but that does not seem right. Can any one help?? Thx

 

[wysiwyg]

sounds like some bad fluid get another bottle and try it

 

[Steelerfan747]

sounds like some bad fluid get another bottle and try it

+1. Get some more fluid as that does not sound normal

 

[Tinola]

where did you get the refractometer? I'm also getting this problem. The seller sent me a replacement, and I'm just waiting for the package to arrive.

 

[cparka23]

Even if the calibration fluid were bad, it shouldn't change from one day to the next (assuming the temperature isn't changing much). You'd just be consistently off by some amount.

Try calibrating with distilled water, and see if that gives you something consistent.

 

[77pm77]

Thank you, It just seems to read high each day. the lfs guy said to calibrate it with RO water. Thats the way he does it. Does anyone ever cal it with RO? How much does the temp have to be off to make it read wrong? Thank you again for all your help!!

 

[Young Frankenstein]

Nope, you should not calibrate with RO. Either get another batch of calibration fluid or a another refractometer. Did you shake the calibration fluid ? If the fluid sits for months it needs a good shaking before use, it says so in the label

 

[77pm77]

Nope, you should not calibrate with RO. Either get another batch of calibration fluid or a another refractometer. Did you shake the calibration fluid ? If the fluid sits for months it needs a good shaking before use, it says so in the label

I think this could be the problem!! I did not shake the cal fluid. The bottle have no instruction on it about shaking but that makes sense. THX

 

[Young Frankenstein]

I think this could be the problem!! I did not shake the cal fluid. The bottle have no instruction on it about shaking but that makes sense. THX

Glad to be of help

 

[MaxCanada]

I think this could be the problem!! I did not shake the cal fluid. The bottle have no instruction on it about shaking but that makes sense. THX

Let us know if it works!!

 

[77pm77]

It seems to be working! Two days with tests that seems to be right so I hope its good. I zeroed the refractometer with Di water, now its looks ok. Thx again!!

 

[Young Frankenstein]

It seems to be working! Two days with tests that seems to be right so I hope its good. I zeroed the refractometer with Di water, now its looks ok. Thx again!!

Use the fluid to calibrate not RO

 

[Fauna Marin]

HI

Sorry guys but there are some things wrong here

Refractometer are made to measure the salinity of Sodiumchlorid luiquids. Not for Seawater. It is of course not correct, to calibrate a test device to the farthest point possible.
Due to the calibration with RO Water/or sodiumchlorid luiquids the refractometer will show a uo to 1.5 points wrong salinity
if you use RO Water it could be more then 2 points wrong.

There is only one correct way to calibrate such a refractometer

1. Clean it well
2. Add a seawater based reference solution on the refractometer
3. Calibrate it then on the ppt chart 35 Salinity ( do not use the other chart which showed density)
4. recalibrate it weekly

rgds claude