For treated water: 4 x 20" Jumbo Cartridges: First stage 1 Micron Meltblown, Second stage 5 Micron KX Carbon, Third stage 5 Micron KX Carbon, Final stage 1 Micron Meltblown; MatriKX Media material is from Coconut fibre, vastly superior to charcoal carbon, with superior life and reduced channeling. Always relubricate the sump orings and the sump threads; this enables hand tightening to achieve a seal, which reduces flattening of the sump orings. Sumps will gradually tighten due to the impact of pump pulsations.