Professional use of pH electrodes for aquariums: liquid for cleaning and for durable or temporary preservation of electrodes. Replaces the solution in the protective caps of the pH electrodes. Easy to use: pour the solution into the protective cap of the pH electrode without diluting it. No distortion of the actual pH: high measuring accuracy due to cleaning and preservation of the electrode. Contains a 3 mol KCl (potassium chloride) solution. Revitalizes the electrodes. Safe storage: small bottle with screw cap. For multiple use. Included in delivery: 50 ml of cleaning and preserving solution for pH electrodes.