I got my new Apex hooked up and I did the calibrations as per instructions. The readings just dont match up. If I take the PH probe and place it back in the PH solution 7. it reads below 7 and the same for 10. Should it not read exactly 7 and 10?? The salt also reads high as well. I checked my salinity with my calibrated milwaukee digital reader and salt is perfect and my eye refractometer reads perfect as well. Thoughts???