Red Sea NO3 : PO4-X NOPOX - Nitrate & Phosphate Reducer (500 ml / 16 oz)

Red Sea NO3:PO4-X is a complete biological reduction solution for controlling nitrates and phosphates in reef and marine aquariums. This carbon-source blend feeds naturally occurring nutrient-reducing bacteria, allowing you to manage nuisance algae and dial in healthier corals without constant water changes.

Looking for more reef chemistry? Browse our Water Treatments.

• Reduces and maintains NO3 (nitrate) and PO4 (phosphate) in reef tanks
• Complex carbon blend promotes beneficial nutrient-reducing bacteria
• Part of the Red Sea Algae Management Program
• 100% reef safe when dosed correctly — do not overdose
• 500 ml / 16 oz bottle — treats a large volume over months

How much should I dose?
Start low — 1 ml per 25 gallons daily — and adjust gradually based on NO3 and PO4 test results. Red Sea's label includes a ramp-up schedule to avoid shocking the system.

Is this reef safe?
Yes, NO3:PO4-X is 100% reef safe at proper dosing. Overdosing can cause bacterial blooms, cloudy water, and oxygen depletion — always test before increasing dose.

Do I need a protein skimmer?
A protein skimmer is strongly recommended. NOPOX feeds bacteria that are then exported through skimming, which is how nutrients actually leave the tank.