Mineralized clay substrate

Also known as: Seachem Fluorite, CaribSea Eco-Complete, Iron-rich clay

Properties

pH effectneutral / inert
KH (carbonate hardness)neutral
GH (general hardness)neutral
Nutrient loadmoderate
Ammonia release initiallyNo
Particle size1 to 5 mm
Longevityindefinite
Cost tiermoderate

How it affects the tank

  • Iron and trace minerals are bound in the clay matrix, releasing slowly to plant roots over years; not a one-shot nutrient dump like aquasoil
  • No water-chemistry shift: pH and hardness stay where they were, making it compatible with any fish species
  • Lower starter nutrient density than aquasoil; pair with root tabs for heavy feeders and column dosing for stem plants
  • Effectively permanent: the clay matrix does not break down and continues to host bacterial colonies and bind nutrients indefinitely

Care notes

Fluorite and Eco-Complete are the established products. Rinse Fluorite extensively before use (it leaves a dust cloud that takes weeks to settle if you skip this). Eco-Complete ships pre-rinsed. Both are heavier than gravel, which helps anchor large plants but adds shipping cost.

Plants that work in mineralized clay substrate

73 aquarium plants in the catalog list this substrate as compatible.

Sources

Data drawn from: seachem-fluorite-spec, caribsea-eco-complete-spec, aquatic-plant-central. Last verified 2026-05-13.

Back to aquarium substrate reference

Further reading