The Evolution RO1000 deionization Add-On Kit (HydroLogic 33006) delivers a 000 reading of no total dissolved solids on your TDS meter. The 33006 deionization Kit removes the last remaining bit of particulates in your water to deliver the highest purity possible. The HydroLogic deionization add-on kit. Helps to customize your indoor hydroponic garden. Removes remaining hard minerals from your RO water to inhibit scale deposits. Catches any difficult-to-remove dissolved particles. Leaves nothing but water for you to use and enjoy.