ATC Refractometer needs constant recalibration

[Randy Holmes-Farley Verified Community Expert]

So I shouldn’t shake the DIY NaCl 35ppt that I made with your recipe either?

I always thought that water would condense on the lid, leaving saltier water in the solution. My common sense always told me to shake it prior.

Well, ok, if there are large temperature swings that cause condensation on the underside of the lid, then yes, that’s a reason to mix it for a few seconds. Fluids in my fish area never had such issues, but I can see how it might.

when mixing, just avoid driving in little bubbles by mixing too vigorously.

 

[Miami Reef]

Well, ok, if there are large temperature swings that cause condensation on the underside of the lid, then yes, that’s a reason to mix it for a few seconds. Fluids in my fish area never had such issues, but I can see how it might.

when mixing, just avoid driving in little bubbles by mixing too vigorously.

Perfect. I’ll just gently swirl it.

 

[I never finish anythi]

You need the temperature of refractometer and solution to be near the same consistent value (e.g. 22 degrees celsius)... Variation in temperature will lead to variation in readings.

I store my refractometer outside - and I have to wait for a couple of hours for it to get to room temperatureor just put it under armpit for 2 mins

 

[Roli's Reef Ranch]

You need the temperature of refractometer and solution to be near the same consistent value (e.g. 22 degrees celsius)... Variation in temperature will lead to variation in readings.

I store my refractometer outside - and I have to wait for a couple of hours for it to get to room temperature..

Of course, that also applies to the hydrometer which is calibrated at 77 deg. Fahrenheit. I'm into reliable reefing gear, if there is such a thing, and a refractometer has more things that can go wrong with it. Even calibration solution isn't consistent among brands adding yet another element of uncertainty. Just buy 2 brands of cal soln and try them out back to back. I can almost guarantee they're a few ppt apart.