Apex salinity Gauge way off or not

[acropora4u]

So I calibrated my Apex Fusion ithree times in three different packets and every time it registered at 36 PPT so I put it back in the reef tank and it reads 35.5 PPt but when I use my refractometer it says that it’s only 27 PPT I calibrated the refractometer and tested reef again with refractoneter and it still reads 27 PPT and apex says 36ppt. I don’t know what to do here!!!

 

[vetteguy53081]

So I calibrated my Apex Fusion ithree times in three different packets and every time it registered at 36 PPT so I put it back in the reef tank and it reads 35.5 PPt but when I use my refractometer it says that it’s only 27 PPT I calibrated the refractometer and tested reef again with refractoneter and it still reads 27 PPT and apex says 36ppt. I don’t know what to do here!!!

Did you calibrate refractometer?
Also assure salinity probe does not have air bubbles underneath