Refractometer Calibration

[fish1031]

I read on the disease forum that a refractometer had to be calibrated with distiled water at 68degress
I bought the one from this site and it says nothing about 68degress
How am I supossed to get my distilled water to 68degress?
put it in the fridge for awhile?

 

[hot883]

Is it an ATC? It adjust automatically to the temperature? if it is no worries. Place a drop of distilled water on the slide and turn the knob until it reads zero.

 

[fish1031]

i don't know its the one from swf.com

 

[sepulatian]

Originally Posted by fish1031
i don't know its the one from swf.com
Did you buy the RHSN-10ATC The one for $39.99? It comes pre- calibrated. I just bought one.

 

[briandg]

I bought the one on this site also. It came calibrated and checked out good, but after awhile the calibration knob accidentally came loose, throwing it off. If I remember correctly the instructions did say something about calibrating at a certain temperature, but I don't remember the temp. I just put the distilled water in the frige with a thermometer and watched it closely until it reached the correct temp. and calibrated it. If you want, I can go pull my instruction manual and see what temp it said.

 

[fish1031]

Yes I bought the RHSN at 39.99 a week ago.
so i don't have to worry about the temp
just do the distilled until it reads zero and then test?

 

[briandg]

Mine is the RHS-10ATC and on page two of the manual it says "adjustment of refracotometer should be made und the condition of 20 degree C enviromental temperature. And all refractometers have been adjusted to null before they leave our stock."

 

[briandg]

If you just got it, I wouldn't recalibrate, I'd just put some distilled water on it and make sure it reads 0. If the calibration is off, I would calibrate it at the temp stated in the manual. Just my opinion.

 

[fish1031]

ok thx!

 

[sly]

Agreed. You probably do not need a calibration but when you do... Buy some distilled water or use some RO water that you know is good. Let it warm up to room temperature.
Calibration has to be done at 68 F even if it is auto temp adjusting. Find a place in your house that is 68 degrees. Usually a closet is cooler than the rest of your house. Put a thermometer in there and wait for it to stabilize and take a reading. If you find a place that is 68, then place your refractometer there for about an hour. Once the refractometer housing acclimates then you can put a few drops of water on the lense. Turn the adjusting screw until it reads exactly 0 ppm or 1.000 SG. Turn the lock nut to hold the screw in place and you're done.

 

[sepulatian]

I didn't calibrate mine, just checked it against a friends that was dead on. They both matched.

 

[fbm]

They say it has to be exactly 68 degrees to calibrate them. But I have tested this and I found no noticeable difference at all. I calibrated it at 50 degrees, 68, and 82 degrees and it all read exactly the same on my tank. So who knows.

 

[gwh57]

Most instructions say to use RO to cal these devises. It would be better to but the calibration fluid and cal them near where you want them to read. They may be accurate at zero but off some at 1.025. They work with a mirrow that is angled inside the devise. IMO check them with a cal fluid that checks them nearer to the reading that you keep your tank.