Bluelab 2.77 EC Calibration Solution Keeping your nutrient strength meter calibrated is essential for taking accurate readings, which in turn allows you to keep your nutrient solution at the correct strength range. If nutrient concentrations are too weak, plants become deficient and if they are too strong, plants will start to look burnt and overfed. When your meter is properly calibrated, you'll have much more faith in your readings, allowing you to tailor your nutrients to your exact requirements. How EC Calibration Solution Works CF/EC meters need to be calibrated regularly to maintain accurate nutrient strength readings. Plants require certain amounts of nutrition when in the vegetation period and different amounts when in the flowering period – if you don't calibrate your meters on a regular basis then your readings may be off and your plants can suffer.