denitrate 4 L — Biomedia Natural Anaerobic Denitrification | Seachem

Seachem denitrate 4L is the largest size currently available of this porous natural biomedia. Its pore distribution and geometry promote both aerobic nitrification at the surface and anaerobic denitrification at the core of the media. It removes nitrates through the same process as live rock, with increased efficiency by forcing water to filter through its porous structure. The 4L size is the most economical choice for large denitrification reactors, multiple systems, or aquarists who fill several filters. Unlike sulfur-based media, it does not produce hydrogen sulfide.

Main advantages

• Natural anaerobic denitrification — removes nitrates like live rock, with superior efficiency
• Dual function: aerobic nitrification (ammonia, nitrites) + anaerobic denitrification (nitrates)
• High surface area and high bacterial density — porous natural material
• No danger from hydrogen sulfide — unlike sulfur-based media
• Never runs out — permanent biomedia, requires no replacement
• 4L size — the most economical, divisible to fill several reactors or filters

Use in reef and marine aquariums

Denitrate works thanks to its porous structure: oxygen is consumed by aerobic bacteria on the surface, creating anaerobic conditions in the core of the media where denitrifying bacteria remove nitrates. Flow rate is critical for denitrification: at flow rates below 200 L/h (50 US gallons/h), denitrate functions as both an aerobic and anaerobic denitrifying filter. At flow rates above 400 L/h (100 US gallons/h), it functions only as an aerobic filter. If high flow rates are unavoidable, use Seachem Matrix or Pond Matrix.

Instructions for use

• Rinse off the dust before use
• Place in a cartridge filter, chemical filtration module, box filter, or media reactor
• The flow rate must not exceed 200 L/h (50 US gallons/h) for denitrification.
• After a few days of use, nitrate levels should begin to decrease and stabilize at around 4–5 mg/L
• As long as nitrates remain under control, the product is not exhausted.
• Pre-filter the water with foam or cotton wool before adding the denitrate to prolong its lifespan.

denitrate vs Matrix

Both denitrate and Matrix are permanent biomedia that support denitrification. Denitrate is smaller (gravel-sized) and more efficient per volume for nitrate reduction at low flow rates (less than 200 L/h), making it ideal for use in a dedicated reactor. Matrix is ​​larger (10 mm) and supports denitrification at higher flow rates, making it ideal for use in a canister or sump. The 4 L format of denitrate allows for filling a large reactor or combining multiple denitrification systems.

Interview

Nitrate doesn't run out but can become clogged with debris and biofilm. Pre-filtering the water upstream with foam or filter floss significantly extends its lifespan. Rinse periodically with aquarium water if necessary, being careful not to harm the internal bacteria.

Available formats

• 100 ml
• 250 ml
• 500 ml
• 1 L
• 2 L
• 4 L
• 20 L
• 100 L

Why choose denitrate from ReefSolution?

The 4L format offers the best cost per liter in the denitrate range for serious aquarists. It allows you to fill a large denitrification reactor or divide the media between several filters. Combine it with Seachem Matrix in the canister or sump for complete, high-flow biofiltration, and use Seachem Stability to accelerate bacterial colonization. Monitor your nitrate levels with the Salifert Nitrate Test Kit or the Hanna Nitrate Checker.

Frequently Asked Questions

Is the 4L format the most economical in the range?

Yes. The 4L container offers the best cost per liter among commonly available sizes. It allows you to fill a large denitrification reactor or divide the media between a reactor and additional filters. Since the denitrate is permanent, it's a long-term investment.

Can 4L denitrate be divided between several systems?

Yes. The bulk format can be divided between a dedicated denitrification reactor and cartridge filters, or between several aquariums. Keep the flow rate below 200 L/h per reactor for anaerobic denitrification.

How long before we see a reduction in nitrates?

Nitrate levels should begin to decrease after a few days of use and gradually stabilize at around 4–5 mg/L. The exact timeframe depends on the biological establishment of the system, media placement, and flow rate. Seachem Stability accelerates initial bacterial colonization.