Refractometer help
- Thread starter mihali
- Start date
- Tagged users None
FUNGI
2500 Club Member
From what I understand regarding ATC:
AUTO TEMPERATURE COMPENSATION (ATC)There is a lot of misunderstanding concerning the way the ATC feature worksand its effect on the refractometer at different ambient room temperatures.Salinity is a measurement of a mass of salt in a mass of water and thereforedoes not vary with temperature however a refractometer does not measuresalinity directly but measures the refractive index which is then displayed assalinity. The refractive index of a solution does vary with temperaturetherefore the reading that you measure with a refractometer is alwaystemperature dependant.An ATC refractometer has a bimetal strip inside the instrument that movesthe reading scale as the temperature changes to compensate for the changein refractive index.What people do not generally understand is that it is the temperature of theinstrument and not the water temperature that is important as the smallsample of water used for testing will equilibrate within seconds to thetemperature of the refractometer.
AUTO TEMPERATURE COMPENSATION (ATC)There is a lot of misunderstanding concerning the way the ATC feature worksand its effect on the refractometer at different ambient room temperatures.Salinity is a measurement of a mass of salt in a mass of water and thereforedoes not vary with temperature however a refractometer does not measuresalinity directly but measures the refractive index which is then displayed assalinity. The refractive index of a solution does vary with temperaturetherefore the reading that you measure with a refractometer is alwaystemperature dependant.An ATC refractometer has a bimetal strip inside the instrument that movesthe reading scale as the temperature changes to compensate for the changein refractive index.What people do not generally understand is that it is the temperature of theinstrument and not the water temperature that is important as the smallsample of water used for testing will equilibrate within seconds to thetemperature of the refractometer.
FUNGI
2500 Club Member
SOURCE: https://www.theaquariumsolution.com/sites/default/files/downloads/SEAWATER REFRACTOMETER V2.pdf
Its a pretty good read.
Its a pretty good read.
FUNGI
2500 Club Member
You'll be ok with that for a general read until the refrac arrives...
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Ultimate Member
Excellence Award
R2R App User
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
I’ve never understood and do not agree with the assertion by manufacturers that the temp matters for an ATC refractometer calibration. I think they do not understand the implication of the purely mechanical temperature compensation that acts equally well on the standard as it does in the sample.
Randy has a recipe for diy calibration fluid using table salt. I would trust it over a comercial product. The comercial product may or may not be accurate but if it isn't accurate your won't know unless you have something to compare it to.
www.reef2reef.com
Reef Aquarium Salinity: DIY Calibration Standards
Reef Aquarium Salinity: DIY Calibration Standards By Randy Holmes-Farley One of the most important issues facing marine aquarists is providing a suitable environment for their aquaria's inhabitants. Among the important properties for a marine...
www.reef2reef.com
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Ultimate Member
Excellence Award
R2R App User
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
Within the range of the ATC temp correction, and if it works properly, yes, it does not matter.
fishkat
Community Member
Will a different brand of table salt work to make your diy salinity standard?
fishkat
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Ultimate Member
Excellence Award
R2R App User
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
Yes, assuming you weigh it and it is not damp, any brand works.
BriDroid
I glue animals to rocks.
Agree totally! I bought one off Amazon that was WAY off. I now make my own!Randy has a recipe for diy calibration fluid using table salt. I would trust it over a comercial product. The comercial product may or may not be accurate but if it isn't accurate your won't know unless you have something to compare it to.
Reef Aquarium Salinity: DIY Calibration Standards
Reef Aquarium Salinity: DIY Calibration Standards By Randy Holmes-Farley One of the most important issues facing marine aquarists is providing a suitable environment for their aquaria's inhabitants. Among the important properties for a marine...
Yep, happened to me too. I thought I had been running at 35ppt for 18 months only to find out the calibration standard that came with my refractometer was off and I was only at 30ppt.
BriDroid
I glue animals to rocks.
I only figured mine out after I bought a used Ice Cap salinity pen and was like “something is off!”
Similar threads
