Do you need to replace salinity calibration fluid for refractometer?

[joec]

I've had Aquacraft fluid for about 14 months. I'm careful to put the top right back after using.

Do you ever need to replace an old bottle with a new bottle for accurate fluid or not significant?

 

[Randy Holmes-Farley Verified Community Expert]

It never goes bad except for evaporation and/or water condensing into it.

 

[Amps Reef Life]

That's a good question. I have wondered this myself from time to time.

 

[pickupman66]

I have made a habit of not saving it. while it is sealed, i dont trust it. I make fresh calibration solution each time based upon Randy's formula. 1tsp table salt in 163.6 ml of water.