Due to the engineering plastics used in Spectra’s watermakers, we strongly recommend that you only use Spectra storage chemicals (SC-1) or a good quality brand of Propylene Glycol with no Ethyl Alcohol added. Using storage solutions from competing manufacturers, such as Sodium Metabisulfite, will permanently damage the membrane end plugs and the Clark Pump. Never use any chemicals with the system pressurized. Always open the pressure relief valve 1/2 turn. Always follow the instructions for purging the chemicals as shown in the New System Startup section of your manual.