Biofilter System

Biofilter System — helps with nitrite/ammonia control.

Solves: Nitrite/ammonia control
Best for: RAS systems, fish farms
Price range: $50–$2000

Recommended for these conditions

Stable water is disease-resistant water. Biofilter System keeps the parameters that pathogens love to exploit firmly under control.

This is one of the few tools that earns its place in every tank, pond, or grow-out system. It targets nitrite/ammonia control, which sits upstream of nearly every disease we document — fix it here and you prevent problems before they ever show symptoms.

How to use it well

Core of any disease-prevention strategy; never disinfect a running biofilter. Treat it as part of a protocol rather than a magic bullet — it works best alongside good husbandry and the medications matched to your specific diagnosis.

Conditions it helps with

Because it works at the water-quality and biosecurity level, you’ll see this item recommended across the full disease library — from parasites and bacterial infections to the viral conditions that have no direct cure and can only be managed through environment control.

Who it’s for

Best suited to ras systems, fish farms. Typical units run in the $50–$2000 range, depending on capacity and features. Use the inquiry form below to ask about a specific model, request a recommendation for your system size, or get notified when stock and pricing are confirmed.

Care & Usage Tips

Establishment & Cycling

Never clean all filter media simultaneously
The nitrifying bacteria colony lives on the surface of your filter media. Cleaning all media at once — or any of it with chlorinated tap water — wipes out the colony and returns the tank to new-tank cycle state. Clean only one-third of media per month, maximum.
Seed a new filter with established media from a healthy tank
The fastest way to cycle a new biofilter is to transfer 30–50% of established media from a disease-free tank. Running both tanks with the new media inside the established system for 2 weeks pre-colonizes it at near-full capacity before it handles waste.
Run the biofilter 24 hours before adding fish to a new tank
Allow the pump, plumbing, and media to reach thermal and chemical equilibrium before the first fish is introduced. This ensures stable flow, reveals any leaks or pump failures, and allows seed bacteria to begin colonizing.
Do not overstock during the cycling phase
Nitrifying bacteria populations grow proportionally to the nitrogen load they process. Dramatically increasing stocking or feed immediately after cycling creates an ammonia spike that exceeds the bacteria’s capacity to process.
Feed lightly during cycling — ammonia source drives the cycle
The most reliable way to cycle a biofilter is with a pure ammonia source (1–2 ppm target) rather than fish food, which rots and creates inconsistent ammonia levels. The bacteria respond to ammonia concentration, not the source.

Protecting the Biology

Never use chlorinated tap water to clean filter media
Chlorine kills nitrifying bacteria within minutes of contact. If you must rinse filter media, use tank water drawn directly from the aquarium, or dechlorinated tap water. This is the most commonly violated rule in aquarium keeping.
Maintain consistent temperature — fluctuations kill nitrifiers fast
Nitrifying bacteria are sensitive to rapid temperature change. A 10°F (5.5°C) swing kills a significant portion of the colony within 24 hours. This is why disease outbreaks follow power outages, chiller failures, and heater malfunctions.
Dose beneficial bacteria after any antibiotic treatment
Antibiotic medications are non-selective — they disrupt beneficial nitrifying bacteria alongside pathogens. After any antibiotic treatment, test ammonia and nitrite daily for one week and dose a commercial nitrifying bacteria supplement for 7–10 days.
Keep dissolved oxygen above 6 mg/L in the biological filter zone
Aerobic nitrification requires oxygen. Nitrifying bacteria activity drops sharply when DO falls below 4 mg/L. Position the return from your biological filter in a high-flow area and confirm strong oxygenation reaches the media surface.
Keep pH above 7.0 — nitrification halts below pH 6.5
Nitrosomonas and Nitrobacter bacteria essentially stop functioning below pH 6.5, and activity drops significantly between 6.5 and 7.0. In soft-water or acidic planted tanks, monitor pH alongside ammonia to catch cascading failures early.

Frequently asked questions

What does Biofilter System do?

The Biofilter System helps control nitrite/ammonia control — common triggers behind fish disease.

What conditions does Biofilter System help with?

Biofilter System applies across the whole disease library — from parasites and bacterial infections to the viral conditions that can only be managed through clean, stable water.

Who is Biofilter System for?

Biofilter System is a good fit for RAS systems, fish farms. It works for both prevention and active treatment.

How much does Biofilter System cost?

Biofilter System typically costs in the $50–$2000 range, depending on capacity, build quality, and features. Use the inquiry form on this page for a recommendation and current pricing.

How do you use Biofilter System?

What should you know about Establishment & Cycling?

Never clean all filter media simultaneouslyThe nitrifying bacteria colony lives on the surface of your filter media. Cleaning all media at once — or any of it with chlorinated tap water — wipes out the colony and returns the tank to new-tank cycle state. Clean only one-third of media per month, maximum.