Aquatic Life Color Changing Mixed Bed DI Inline Cartridges are the most effective and easy to use DI cartridges available - filled with Aquatic Life MBD-30 Nuclear Grade resin. Features: Cation and Anion resins (H+ and OH-) remove the remaining total dissolved solids (TDS) from membrane-filtered water. Clear cartridge takes the guess work out of determining when resin is exhausted. Aquatic Life MBD-30 Nuclear Grade resin changes from blue to yellow, then tan to white when depleted. Includes mounting clips to attach to all standard size RO membrane housings.