JBL ProFlora Cal is a complete set with a liquids requried for professionally calibrating and storing pH sensors (electrodes).https://www.aquaristikshop.com/aquaristic/JBL-ProFlora-Cal/127910/
- Ilya K. wrote about JBL ProFlora Cal in 2016:
This is a very good and accurate kit to calibrate the CO2 electrode system of JBL. The set includes 4 bottles: water pH4, pH7 water, distilled water and the stabilization solution for storage of electrodes. Also included are measuring cups. Always use only products from JBL for supplying carbon dioxide to the aquarium, since they are the most comfortable and ergonomic.