Multi-microbe blend, Liquid

BioRas® TAN

BioRas® TAN helps ensure your recirculating aquaculture system’s biofilter is ready when planned and moves more rapidly to target biomass and feed-rate. That gives you more flexibility and acceleration of new biomedia startup and can cut restart-related downtime after disinfection by up to 33%. 

Available in 4.5L. 

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Key Benefits Description Safe handling
  • More predictable startup

    Biofilter start-up should take between 8 and 16 weeks, but it’s an unpredictable process. That’s a challenge when you’re planning for the arrival of fish stocks. With BioRas® TAN you get more reliable, predictable results. You also cut the time it takes to move to target biomass and feed rate, giving you more flexibility in your schedule and helping you avoid premature introduction of fish. The end result is improved production performance in year 1 of new operations and a higher chance of long-term success.

  • Faster restart, less downtime

    From mandatory regulatory restarts to decontamination protocols, every biofilter restart means three to five weeks lost production time. That eats into the profitability of your operations. BioRas® TAN cuts the time it takes to reach target biomass and feed rate in restarts by up to 33%. That means far less restart-related downtime, more production cycles and higher profitability for your facility.

  • Increased biosecurity

    The specially-selected strains of nitrifying bacteria in BioRas® TAN are cultured in optimal conditions for the highest possible product purity. That means they pose no biosecurity risk to the facility.

  • Easier planning

    The BioRas® TAN precision dosing calculator makes planning easier. Simply give us your unique system parameters and we’ll give you tailored dosing recommendations.

Biofilters are the heart of every recirculating aquaculture system. Their nitrifying bacteria convert ammonia and nitrite excreted in the system to non-toxic nitrate. But the slow, unpredictable growth and sensitivity of these bacteria can cause problems in biofilter startups and restarts. BioRas® TAN is a blend of specially-selected strains of nitrifying bacteria. It delivers faster, more predictable results. 

This product contains both enzymes and microbials. While both are safe to use in consumer applications, they must be handled correctly in production/working environments to ensure workers’ safety.

Especially, repeated inhalation of enzyme dust or aerosols resulting from improper handling may induce sensitization and may cause allergic type 1 reactions in sensitized individuals.

Please follow the precautionary handling recommendations below:

  • Avoid breathing dust/fume/gas/mist/vapors/spray
  • Avoid contact with eyes, skin, or clothing
  • In case of inadequate ventilation wear respiratory protection
  • IF INHALED: Remove person to fresh air and keep comfortable for breathing
  • If experiencing respiratory symptoms: Call a POISON CENTER or a doctor
  • Store in a dry place. Store in a closed container
  • Dispose of contents/containers in accordance with local regulations

For more safety information, download the manual for Safe-handling of microbial products  and watch the video Safe-handling of enzymes. Full series of safety videos can be found here.


Efficacy of BioRas® TAN in biofilter restart: Get to desired TAN and reduce risk of nitrite spikes ​

BioRas® TAN reached <0.5mg/L TAN levels in 10 days: 33% faster than control (15 days)

After the addition of 20mg/L of ammonium, BioRas® TAN significantly reduced nitrite spikes in comparison with control 


Trials Conducted CRO in Chile in 6m3 system/1.8m3 biofilter, Conditions: 13 °C/ 12ppt salinity. Biofiliter disinfected by soaking in 250 mg/L paracetic acid and 50% NaOH solution for 12h each. Recovery of nitrification was monitored for 30 days post-disinfection. NH4OH was fed when TAN readings reached <0.4mgL,  System was challenged at day 26 with a 20mg/L spike of ammonium (red line). 

How nitrifying bacteria convert ammonia and nitrite to non-toxic nitrate in RAS aquaculture

Buildup of ammonia and nitrite in RAS impacts fish health. Through nitrification, bacteria in the biofilter break ammonia and nitrite down into non-toxic nitrate.    

Ammonia and nitrite excreted in recirculating aquaculture systems (RAS) can build up to toxic levels. That creates stress on fish stocks and ultimately puts their health at risk. That’s why the nitrifying bacteria in RAS biofilters are so crucial to overall productivity in RAS aquaculture. They break down ammonia and nitrite to non-toxic nitrate in a two-step process known as nitrification. Optimal pH for nitrification is 7.0 to 8.5.  

In the first step, ammonia-oxidizing bacteria (AOB) oxidize ammonium ions NH4+ to nitrite NO2-. In the second step, nitrite-oxidizing bacteria (NOB) oxidize nitrite to nitrate NO3-. That prevents the built-up of toxic ammonia and nitrite for improved fish health and overall production.  

How to use

Only dose once disinfection is completed. Take BioRas® TAN from cold storage and allow it to reach operational temperature prior to dosing. Dose it into the biofilter inlet. 

Safety, handling and storage

Refrigerate BioRas® TAN upon receipt and throughout the period of use. Do not allow the product to freeze. Avoid excessive skin contact. Wash hands thoroughly with warm, soapy water after contact. Avoid contact with eyes.

Get faster, more predictable start-up and restart

Get faster, more predictable start-up and restart

Get faster, more predictable start-up and restart

Find out how BioRas® TAN can help ensure biofilters are ready when planned and move more rapidly to target biomass and feed-rate.