Aquatic Life Classic Deionization 10-Inch System with Color Changing Mixed Bed Resin Cartridges for Aquariums. Water purity is usually measured by the amount of Total Dissolved Solids (TDS) in the water. After water is filtered by an RO Membrane (not included), there is usually a small amount of TDS left in the water – for aquarium applications it is important to remove the remaining TDS from the water. This is accomplished by filtering the water through a resin that is charged with Cation and Anion resins (H+ and OH-). As the resin absorbs the TDS, it will change color. When the entire resin has changed color, it is time to replace the DI Cartridge. Features: Mixed bed resin contains Cation and Anion resins (H+ and OH-) remove the remaining total dissolved solids (TDS) from membrane-filtered water - The resin changes to amber color when media is exhausted - Includes 2 x 10" Mixed Bed Color Changing Resin Cartridges (Item No.330091) - Included mounting brackets, wrenches and ¼ inch tubing make installation and maintenance easy! Item #540235

Aquatic Life Dual Deionization & Spot Free Car Rinse Systems - B074CG5G5H