I've calibrated my conductivity probe on my new P4 in the 50ms fluid with the fluid floating in the sump (in a bag) next to the temp sensor and it's currently reading 1.0241 whereas my refractometer reads 1.026 - 1.027 (temp compensating D-D). The refractometer is calibrated using 35ppt fluid.

Which do I trust? Can I adjust the reading of the probe to match the refractometer?

Thanks