Refractometer

I have a Refractometer with ATC and I use Ro water to calibrate it. Is that how every one else calibrates theirs? In the instructions it say that the temp in the room should be 68 when it is calibrated. I dont really understand why.
Adam

 

I use a special saline solution I bought when I purchased my refractometer. It has a salinity of 1.035, so I just adjust it until the line aligns with that number. I know the temperature is important when measuring the salinity because different temperature water can hold a different amount of salt, so you may get a lower or higher reading depending on the temperature of the water.

 

68 degrees? Sheesh what do they expect Eskimos to be using these things?

The lowest my house ever gets is 78.

 

68 degrees! i live in Buffalo, and we can't afford to keep the house that warm! lol. I used distilled water to calibrate mine. The saline solution is the most accurate. Lets say the rooms 78.. if you calibrate it with distilled or saline at that temp, you will get an accurate reading of your tank. I think the ATC is about the temp of the water. I drip a drop.. lol on the refracto, then wait a minute.. then measure,, I think Otty suggested that in another thread, along with that saline calibration fluid.

 

ATC- Automatic Temperature Compensation

Salinity changes with temperature.......Specific Gravity doesn't.

Using 53 microSiemens fluid and calibrating to 35 PPT salinity is far more accurate than calibrating to zero using distilled or RO/DI water at the wrong temperature. It's cheap too. salinity calibration fluid - Google Search

EDIT: Sorry about that. I made a boo boo. Specific Gravity does change with temperature. ::sigh:: that's what I get from doing things from my head late at night.

 

i got that solution but can't figure out what to do with it, always used distilled water. Do i just drop a couple drops, wait a minute then set it to 35 ppt? I'm rather confused...

 

+1 It's on my list for my monthly fish order.. Christmas every month for my tank.

 

Yes set it at 35 ppt... Specific Gravity like he said is affected by temp.. so by calibrating that at 35 ppt.. which is what the solution is at is gonna give you an accurate reading no matter the temp of your tank water.

 

muchos gracious senior