Pumice (Lava Rock)

Physical and Biological Properties

• Porous structure:
  Pumice has a high specific surface area (up to 300 m²/L depending on grain size), providing an excellent habitat for nitrifying bacteria (Nitrosomonas, Nitrobacter, etc.), which ensure the biological breakdown of ammonia and nitrites.

• Low density:
  About 0.8–1.0 kg/L, making it easy to use in trickling filters, submerged biofilters, or fixed-bed systems.

• High durability:
  It is a chemically inert and stable material, releasing no harmful substances into the water.

Applications in Aquaculture and Aquariums

1. Biological filtration:

   • Used in trickling filters, percolating filters, or submerged biofilters.

   • Can be combined with other filter media such as plastic beads, gravel, or foams.

2. Complementary mechanical filtration:

   • Captures coarse particles upstream of biological treatment.

   • Often used as a prefilter before sand or biological filters.

3. Bacterial support in recirculating systems (RAS):

   • Common in Recirculating Aquaculture Systems for nitrification.

   • Also suitable for planted aquarium filters, settling tanks, and pressurized filters.

Advantages

• Excellent bacterial colonization capacity.

• Lower cost compared to synthetic media.

• Long lifespan (>10 years).

• Eco-friendly and naturally available material.

Limitations

• Can clog if water contains too many suspended solids (good prefiltration is required).

• Slight pH variation may occur initially (rinse before use).

• Heavier than plastic media in fluidized filters.