Black corundum content of carbonized silicon, mainly produced by sintering the industrial waste.
Features: very hard to disintegrate (under normal use almost no disintegration), will not release substances to impact water quality. Contains no nutrition at all.
Advantages:
● fish has a strong color effect on the dark sand background,
● corundum sand helps to maintain water temperature stability,
● won't produce any dust by disintegration,
● good for aquatic plants that create beautiful landscape view.
Dark sand environment makes appeasement effect on timid small light fish, Hydra and other insects are not easy to breed, black shrimp and rose shrimp show more vivid colors, algae attaches shallow (it’s easy to clean, and shrimp also eat very clean)
Disadvantages: due to high temperature sintering, it can form needle-like crystal - be careful not to hurt while washing it. If the sand been sucked into filter pump, easy to wear fan. No nutrition require use the root fertilizer for water plants.
Applicable for soft and hard water fish