Seachem · Inert nutrient
Seachem Flourite Black
United States · Black · grain 1 to 2 mm (gravel)
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TL;DR, Seachem Flourite Black
Flourite is a porous baked clay gravel manufactured by Seachem. Planted tanks intended to run for five-plus years without substrate replacement.
Full specs
- Brand
- Seachem
- Country of origin
- United States
- Category
- Inert nutrient
- Colour
- Black
- Grain size
- 1 to 2 mm (gravel)
- pH target
- Neutral
- pH effect
- Neutral
- KH effect
- Neutral
- Ammonia release
- None
- Nutrient content
- Medium (iron-rich clay base)
- Buffering longevity
- Permanent (never exhausts)
- Recommended water
- Tap or RO (any hardness)
- Difficulty
- 2 / 5
- Shrimp-safe
- Yes
- Best for
- Long-term planted tanks, hard-water regions, planted livebearer tanks
How it works
Flourite is a porous baked clay gravel manufactured by Seachem. The substrate is naturally iron-rich and the porosity allows plant roots to grip and extract nutrients over time. Unlike active soils, Flourite does not break down or exhaust. A Flourite substrate is essentially permanent.
Best use cases
Planted tanks intended to run for five-plus years without substrate replacement. Hard-water aquariums where active soils' pH-lowering effect would be undesirable. Tanks that mix planted scaping with fish species that need alkaline water.
Common mistakes
Flourite is notoriously dusty out of the bag. Aggressive rinsing in a bucket before adding to the tank is required, otherwise the tank stays cloudy for days. Even after rinsing, the first water change pulls some residual dust.
Pro tips
Mix Flourite Black with a small amount of Flourite Sand (a finer-grain variant) for a smoother visual finish. Pairs well with Seachem's complete liquid fertiliser line for a single-brand workflow.
Plants that thrive in this substrate
Hand-curated pairings based on the substrate category, not a relational query.
- Vallisneria SpiralisVallisneria spiralisLong-runner background grass that pulls iron and trace minerals from Flourite/Eco-Complete.
- Amazon SwordEchinodorus grisebachiiTolerates inert nutrient substrates well if root tabs are dosed every 3 to 6 months.
- Cryptocoryne WendtiiCryptocoryne wendtiiAdapts to inert substrates with the help of root tabs at planting time.
- Bacopa CarolinianaBacopa carolinianaStem plant that draws most of its nutrients from the water column anyway, so inert is fine.
Sources & further reading
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