NO3:PO4-X Nitrate & Phosphate Reducer - Red Sea

Red Sea Nitrate & Phosphate Reducer
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  • Red Sea Nitrate & Phosphate Reducer
  • Red Sea Nitrate & Phosphate Reducer

Quick Overview

Prevent algae breakouts by removing the nitrates and phosphates in your reef tank. NO3:PO4-X Nitrate & Phosphate Reducer from Red Sea is a complex of carbons each with a different strain of microorganisms in a reef ready solution.

Three Sizes Available

  • 500mL

  • 1000mL

  • 5000mL

  • Quick Overview

Prevent algae breakouts by removing the nitrates and phosphates in your reef tank. NO3:PO4-X Nitrate & Phosphate Reducer from Red Sea is a complex of carbons each with a different strain of microorganisms in a reef ready solution.

Three Sizes Available

  • 500mL
  • 1000mL
  • 5000mL

NO3:PO4-X Nitrate & Phosphate Reducer - Red Sea

94% Recommend this to a friend (29 of 31)


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500mL NO3:PO4-X Reducer
SKU: 208218
Preferred Reefers earn 75 points
1000mL NO3:PO4-X Reducer
SKU: 208219
Preferred Reefers earn 125 points
5000mL NO3:PO4-X Reducer
SKU: 210940
Preferred Reefers earn 470 points

Availability: In stock


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Product Questions

If my tank is running very low to 0 nitrate and phosphates is this still recomended if I want to build benificial bacteria like the product claims?
Question by: Nick Castillo on Apr 24, 2016 7:13:00 PM
Great question!
You will not need to use this product if your levels are undetectable. While this provides food for bacteria it will most likely result in over dosing and issues such as excess bacteria such as Cyano.
Answer by: Connor (Admin) on Apr 27, 2016 2:19:00 PM
while using NOPOX can i still run my U/V sterilizer?
Question by: brent matura on Jan 13, 2016 4:20:00 AM
Great question!
Typically with Bacteria growth systems such as NoPox, Zeovit, and Bio-pellets it is not recommended to run UV sterilizers as they can keep the bacteria from repopulating in the tank as needed! Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jan 13, 2016 1:48:00 PM
If all is reading well is this safe to use daily! Just to keep all under control
Question by: delores on Apr 13, 2016 10:52:00 AM
Great question!
This is recommended for daily use for keeping up with nitrate levels. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Apr 13, 2016 3:17:00 PM
Can I use Red Seas No3PO4x added in with my ATO/Kalk? I make up a weeks worth at a time. I'm away from home frequetly so the daily measure and addition of the liquid is not possible.
Question by: Mike Ornellas on Apr 15, 2016 5:55:00 PM
Great question!
It may be possible however you would need to perform some math by seeing how much Top Off water you add each day. We do not recommend this as the nopox will settle out in the RO water and not be mixed evenly. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Apr 20, 2016 12:22:00 PM
I recently moved and setup my reef tank. The tank has begun showing diatoms. Is this product recommend during the tank cycling process? Will it help rid my tank of diatoms?
Question by: Eric Thatcher on May 3, 2016 10:35:00 AM
Great question!
This product will decrease nitrate levels in the tank by feeding the bacteria and growing the population that additionally consume nitrates. Diatoms will typically not be impacted and usually will fade after a few days without light or siphoning out.
Answer by: Connor (Admin) on May 3, 2016 4:59:00 PM
I travel a lot with my job so I can't always dose daily. Can NOPOX be added with a dosing pump?
Question by: Ryan Lowder on Jun 1, 2017 9:28:00 PM
There should be no issues with setting this up with an automated doser. We know of quite a few customers doing just this.

Happy reefing!
Answer by: Zack (Admin) on Jun 8, 2017 10:58:00 AM

Full Details

Red Sea NO3:PO4-X Manual


Red Sea's NO3:PO4-x is a part of their Algae Management Program that combines highly effective, controlled biological reduction of nitrates and phosphates for all reef and marine aquariums. Between testing and dosing the proper additives, nutrients in the aquarium can be easily managed with no undesirable effects. NO3:PO4-x helps promote naturally occurring nutrient-reducing bacteria that already exist in your aquarium. 


  • Reduces and maintains NO3 and PO4
  • Cose Effective
  • 100% Reef Safe (do not overdose)
  • Nitrate and Phosphate reduction in a controlled setting


Dosage Guide:

We highly recommend starting with half the recommended dose for your aquarium type and using high-quality Nitrate and Phosphate test kits during implementation. Keeping a steady dosing regime is key, and daily dosing is highly encouraged. We prefer to use a dosing pump system for daily dosing, which keeps the doses very precise and reliable.

Aquarium Type


NO3 Level


PO4 Level

Average Daily

Dose of NO3-PO4-X

Mixed Reef 1-2ppm 0.08 - 0.12ppm 2mL per 25 gallons
SPS Frags 1-2ppm 0.08 - 0.12ppm 2mL per 25 gallons
SPS Dominant 0.25 - 0.5ppm 0.01 - 0.02ppm 1-2mL per 25 gallons
Ultra Low Nutrient SPS 0ppm 0ppm 1-2mL per 25 gallons
Marine Fish <10ppm <1ppm 3mL per 25 gallons



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  • as advertised By iMygdala on 9/11/2017

    The instructions are clear even if the dosing cup is rudimentary. I was warned to watch for over-suppresion of nitrates and phosphates. Red Sea requires weekly testing and dosing adjustments based on results and this had been provided a very soft, gradual transition into better numbers. Instructions state that there is no need for a GFO reactor but I have continued to run one and phosphates have been stable between 0.08 and 0.04. Skimmer is a must, and this is stated in the instruction; the sludge coming out of the skimmer is much darker and disgusting than before dosing. Back to measuring cup.... For the measured nitrates, the instructions stated that the tank needed three cc's per 25 gallons. The tank is a 43 gallon Red Sea Reefer which works out 5.16 mL's, but the measuring cup just ain't close to that good. Which makes me think that the dosing is probably good if its within 20%
  • Smells like hell but works By Chad on 9/9/2017

    By the smell it is clearly denatured alcohol, however, THIS STUFF WORKS. Had a spike in nitrates while I was on honeymoon to nearly 50. in about a month is is down to 5. Having an amazing Skimz skimmer helps too though.
  • Great product By con on 3/27/2017

    This product works great I'm very happy with my purchase! But I would recommend dosing half of what it says to dose for your first use.
  • Nitrate cut in half By Juan on 3/26/2017

    I received my nopox on Friday with a Redsea nitrate test kit today Sunday three days of use My nitrates are half off while they were on Friday
  • Works as advertised By Hasso on 1/13/2017

    Works very well but in my case took almost 4 months for No3 to go from 35ppm to 3ppm
    And Po4 0.00ppm
  • Works Great By Dave on 1/1/2017

    I've been using this for a couple of years now and I must say nothing gives me the peace of mind that my nitrates will be kept in check. I like to feed my fish and corals and have the freedom to do so with the help of Red Sea.
  • works great By Dustin on 12/9/2016

    Was skeptical at first until I read some reviews and thought I would give it a try. In about a week was able to lower nitrates from 7 ppm to 0 and phosphate from .42 to 0. I was only going to use this product until my new lid came for my GFO reactor now considering using this full time!
  • worked brilliantly By Terry on 11/23/2016

    I had a persistent difficulty getting nitrates under 5 ppm and SPS started dying and I had cyano problem. I nuked the cyano with chemiclean and started using nopox. AT 12 ml/day I was down to near zero nitrates in a few days (on a 200 gallon tank). I've dialed it into 8 ml/day now and that keeps nitrates at near zero and my coral is doing great.
  • Excellent Product! By Shane on 9/12/2016

    No3Po4-X is an amazing product. For over 5 years I have constantly fought Nitrates and Phosphates. With this product I was able to get my Nitrates down from 20 to under 5 and my Phosphates from over .10 to under .02 in less than a week using Salifert to test. Maintenance dose is at 1ml a day on my 34g tank keeping nitrates stable at about 1ppm and phosphates undetectable with Salifert which im assuming is around .02 or so. Do not overdose this product. If you come back to your tank and you notice white film you have overdosed and need to cut the dose in half and test.
  • Excellent Product By Dave on 8/24/2016

    No3:Po4-X has become an essential item for my reef system. It allows me to feed my fish without the worry of high nitrates.
  • ?? By Darrin on 7/4/2016

    dont know about this, worked awesome on my 55 gal tank dosing 12ml a day kept my nitrates at 0, dosed 19 to 30 mils a day on my 125 gal tank nitrates never below 50 and had some clear slime clogging up everything
  • This is the "silver bullet"! By Dick on 5/16/2016

    I have a BioCube 29, in operation successfully for over 4 years. I put every modification on it that it can accommodate: Hydor skimmer, InTank media tower, Innovative Marine bio-pellet reactor, Maxspect LEDs, upgraded Cobalt pump, etc. I have been successfully growing softies and some SPS. I have a montipora plate that has grown from quarter size to 8 inches in diameter. However, for all this time I have been fighting nitrates and phosphates. Nitrates have always been in the range of 12-16 ppm, and phosphates .06-.10. I've carbon dosed with Continuum Microfuel; tried two different brands of bio-pellets; tried several different brands of GFO; have been religious about weekly water changes (about 20%) and changing my Purigen pillow every two months. I finally decided to try NO3:PO4-X, and I'm glad I did! After one week my nitrates dropped to 4 ppm and my phosphates to .02. After the second week my nitrates are at 1 ppm and my phosphates are at 0. I followed the directions carefully. Resist the temptation to overdose. This stuff works where nothing else has, and I could not recommend it more highly.