Refractometers, How often do you recalibrate? Is one model actually better than another?:

[Pelagikos]

How often do you recalibrate?
Do you find that there are better models that might not need recalibration as often or have more accurate/consistent readings?

 

[Quietman]

I used to re-calibrate weekly. Saw very little drift in between so now it's probably monthly or more. Still no big drift but I do like confirming that once in a while. I got the standard refractometer with LED light and since it's spot on (maybe half a mark every month) don't see a need for anything more expensive. If this ever does start to go out more - I'd very likely pick up the same type with the exception of the LED. Completely useless to me. Not sure it's my eyes or the LED, but I can really only read it when holding to light (window ever better).

 

[redfishbluefish]

If I had to pick frequency of calibration I'd guess about once a year. I do two water changes per month and always measure my DT during these changes to more or less verify the refractometer is correct. If that number is not 1.026, then I recalibrate.

 

[Pelagikos]

I used to re-calibrate weekly. Saw very little drift in between so now it's probably monthly or more. Still no big drift but I do like confirming that once in a while. I got the standard refractometer with LED light and since it's spot on (maybe half a mark every month) don't see a need for anything more expensive. If this ever does start to go out more - I'd very likely pick up the same type with the exception of the LED. Completely useless to me. Not sure it's my eyes or the LED, but I can really only read it when holding to light (window ever better).

Good to know that the LED doesn't make a big difference. I didn't even know they made one equipped like that!
The one I have is just your basic cheapo and it seems to be doing well. (1 year on) sometimes when I check salinity and it's always spot on I kind of second-guess my reader.
Just wasn't sure I wasn't missing out on something better!

 

[Pistondog]

Models that use a puddle of water, milwaukee ma887, are more prone to user temperature errors than the classic drop or 2 hold to your eye models.
Have to wait for the water to equalize with instrument.
Calibration should be checked yearly.

 

[Quietman]

Good to know that the LED doesn't make a big difference. I didn't even know they made one equipped like that!
The one I have is just your basic cheapo and it seems to be doing well. (1 year on) sometimes when I check salinity and it's always spot on I kind of second-guess my reader.
Just wasn't sure I wasn't missing out on something better!

Welcome to Reefing! There's always something better or at least more expensive. I tend to go with 'good enough' and the 'if it's not broke, don't fix it' type mentality. At least until the new and improved prove their usefulness and cost because new and improved never means cheaper. :)

 

[Nachopapa]

I used to re-calibrate weekly. Saw very little drift in between so now it's probably monthly or more. Still no big drift but I do like confirming that once in a while. I got the standard refractometer with LED light and since it's spot on (maybe half a mark every month) don't see a need for anything more expensive. If this ever does start to go out more - I'd very likely pick up the same type with the exception of the LED. Completely useless to me. Not sure it's my eyes or the LED, but I can really only read it when holding to light (window ever better).

I agree, I have the LED version and it makes reading the line more difficult than just using a nearby light or window.

 

[diverjm]

I strictly use VeeGee brand refractometers. They are more expensive but last a lifetime. I use them for homebrewing and my reef tank.

 

[Tamberav]

How often do you recalibrate?
Do you find that there are better models that might not need recalibration as often or have more accurate/consistent readings?

Ya the VeeGee one pretty much almost never loses calibration but it also costs around $100

They are Lab grade not Amazon/BRS grade ;)

 

[Spare time]

I check if its calibrated every time before I use it. It takes a few seconds so why not.

 

[diverjm]

Ya the VeeGee one pretty much almost never loses calibration but it also costs around $100

They are Lab grade not Amazon/BRS grade ;)

Precisely! I’ve never lost calibration on either one of my VeeGees. I’ve had my home brew one for years!

 

[exnisstech]

I not even sure of the brand I use. I only calibrate it when it gives an unusual reading. My DT salinity doesn't really fluctuate and I know exactly how much salt to add when I mix a batch to get 1.025 so if it shows anything different I'll check it.

 

[PigDaddyF15E]

I use a bulb hydrometer to get a measurement then calibrate my refractometer off of that. I just found the fluid calibrations to be too inconsistent. This works and it's very accurate.

Granted they all have a certain margin of error.

 

[Quietman]

Plus when you realize that tropical reefs experience changes in salinity naturally from storms, runoff, river outflows, seasonal variations in currents, it's not really needed or perhaps desired to keep it at 1.026 +/- 0 always. I've seen recommendations that anywhere from 34 - 36 is going to be just fine. So I'm very confident that my calibration drifting a half point over a month is more than good enough.