Rinse before use. Use in a fine mesh filter bag such as Seachem's The Bag. Each 225 mL treats up to 1,000 L (250 US gallons) for up to six months. Exhaustion is indicated by a pronounced discoloration of the beads to dark brown or black.

Regeneration: Once it is exhausted, it can be easily regenerated with a solution of bleach and water. Soak in a 1:1 bleach:water solution for 24 hours in a non-metallic container in a well-ventilated area, away from children. Use regular 8.25% hypochlorite household bleach (non-scented, no dyes, do not use a splash-less bleach). Rinse well, then soak for 8 hours with a solution containing 3 tablespoons of alpha, or equivalent dechlorinator per cup of water. Rinse well. For freshwater use, soak beads for 4 hours in a solution containing 2 tablespoons of buffer (Seachem Discus Buffer or Neutral Regulator) per cup of water. The original color and full activity should now be restored and purfiltrum is ready for reuse. Caution: some slime coat products may permanently foul purfiltrum and render regeneration difficult. Do not reuse if odor of bleach/chlorine is detectable. If uncertain, soak beads in small quantity of water and test for residual chlorine with a chlorine test kit.