Hanna pH 4.0 Calibration Solution 500ml Size:20 ml The vegetative growth stage demands miscnutes The vegetative growth stage demands well rounded nutrition to establish strong roots and lush foliage Y splitter and RJ12 4 ft cable to connect to the Hydro x Hanna calibration buffers have the lot number and expiration date clearly marked on the label and are air tight with a tamper proof seal to ensure the quality of the solution Air tight bottle with tamper proof sealEnsures quality and freshness of solutionColor coded label for easy pH buffer value identificationEasy to identify different buffer valuesSolution does not contain any dyes that may stain the reference cell of a pH electrode