Aquasoil (aquarium plant substrate)

Properties

In a system

• Leaches ammonia for roughly 2-6 weeks after wetting (ADA Aquasoil Amazonia can spike ammonia to around 2 ppm); designed for fishless planted aquariums where this dose feeds plants during cycling
• In an aquaponics loop that ammonia release spikes levels well past the ~0.02 mg/L toxicity threshold for most fish, and a fresh, unestablished biofilter cannot oxidize it fast enough, so fish die
• Acidic: it softens water and holds a slightly acidic pH (around 6.6-6.8), unlike the near-neutral conditions an aquaponics biofilter prefers
• Breaks down into mud over about 2-3 years, clogging pumps, plumbing and grow-bed drains
• Costs several times what LECA or expanded shale costs, for an inferior outcome in a fish-bearing system
• Sometimes recommended online by people conflating aquaponics with high-tech planted aquariums, which have opposite requirements

Notes

There is no situation in which aquasoil is a better choice than LECA or expanded shale for an aquaponics media bed; its deliberate ammonia release, made for fishless planted-tank cycling, is actively dangerous to fish. The closest legitimate use is a planted aquarium with no aquaponics component.

Further reading

• Building a media-bed aquaponics system
• Aquaponics water chemistry: balancing pH for fish and plants