DI Resin Cartridge 10" Color Changing Reefkeeping SaltwaterAquariums Know when to change your COLOR CHANGING DI RESIN TYPE ::ANION DI RESIN Know when to change your prefilters and membranes and verify pump pressure with a large print glycerin filled pressure gauge built into the frame This filter pack replaces one of the carbon block filters with an activated granular catalytic carbon filter which is specifically designed to remove any chloramines that may get added to your city water Standard Features : ResinTech MBD 30 is a 1:1 volumetric mixture of CG8 H (an amber colored hydrogen form cation resin) and SBG1P OH ID (a dyed hydroxide form type 1 porous strong base anion resin) rinsing and test purposes