Phosphate at 0/undetecable nitrates wont drop past 25ppm using NO3PO4-X

[Factory909racer2]

So ive been using NOPOX for about 5 months and phosphate is un-detectable and nitrates wont drop below 25ppm. Its weird too because it seems everyone else has the opposite problem with NOPOX. I have heard that NOPOX needs phosphate to be present to reduce nitrate as the bacteria need both to reduce nitrates?

Tank specs
120G display
36G sump

Nitrate: 25-40ppm (sera test kit)
Phos: 0.00 undetectable with salifert kit or red sea
CA: 450 (salifert)
ALK: 11 (sera)
MAG:1220 (red sea)
Ammonia: undetectable
Nitrite: undetectable

 

[Mark Waltermire]

What type of skimmer are you running on this tank?

I have also seen people dosing phosphate back in so that the bacteria can help to lower the nitrate. I personally do not like adding more things to the water and would rather find the route of the problem. How often and what percentage water changes are you doing?

 

[clover128]

Do you have any algae issues in DT? Do you run a refugium? If so, how well is it growing?

 

[Velcro]

I was in this situation. I dosed phosphate but honestly nitrate reduction was slow at max no3po4x dose. I ended up just doing a series of 40% water changes to lower nitrate to target. The nitrate is staying low with continued dosing.

 

[ChrisOFL]

6NO3- + 5CH3OH = 3N2 + 5CO2 + 7H2O + 6OH
This is the equation for dentrification. It basically says that nitrate plus a carbon source will result in nitrogen gas, carbon dioxide, water, and hydroxide. No phosphate is required for this reaction, only anearobic bacteria conditions can cause this to occur however. I have tried dosing phosphates in my tank up to 0.3ppm and within 12 hours all phosphates would be removed by bacteria but nitrate reduction would be no different in speed or amount. Sulfur dentrification is even more effective but will reduce alkalinity and is something that has to be closely monitored.

 

[Factory909racer2]

Do you have any algae issues in DT? Do you run a refugium? If so, how well is it growing?

I run a SCA-303 skimmer and i have a small/medium sized refugium full of cheato that i take about a basketball size ball out every month.

 

[Factory909racer2]

6NO3- + 5CH3OH = 3N2 + 5CO2 + 7H2O + 6OH
This is the equation for dentrification. It basically says that nitrate plus a carbon source will result in nitrogen gas, carbon dioxide, water, and hydroxide. No phosphate is required for this reaction, only anearobic bacteria conditions can cause this to occur however. I have tried dosing phosphates in my tank up to 0.3ppm and within 12 hours all phosphates would be removed by bacteria but nitrate reduction would be no different in speed or amount. Sulfur dentrification is even more effective but will reduce alkalinity and is something that has to be closely monitored.

Nitrates have come down but not to where i would like to see them around 2-5ppm. I think im just going to do a few big water changes to get them a bit lower and hope the nopox will keep them low like above mentioned. Glad phosphate isnt the issue haha i wouldnt want to add something in everyone else is trying to get out.

 

[Randy Holmes-Farley]

The phosphate may not actually be low enough to limit denitrification, but I’d want to raise it anyway, and dosing it may be a good idea. [emoji3]

 

[Randy Holmes-Farley]

6NO3- + 5CH3OH = 3N2 + 5CO2 + 7H2O + 6OH
This is the equation for dentrification. It basically says that nitrate plus a carbon source will result in nitrogen gas, carbon dioxide, water, and hydroxide. No phosphate is required for this reaction, only anearobic bacteria conditions can cause this to occur however. I have tried dosing phosphates in my tank up to 0.3ppm and within 12 hours all phosphates would be removed by bacteria but nitrate reduction would be no different in speed or amount. Sulfur dentrification is even more effective but will reduce alkalinity and is something that has to be closely monitored.

That equation shows it is not needed for denitrification, but it is still needed by those bacteria for other purposes. [emoji3]

 

[ChrisOFL]

That equation shows it is not need for denitrification, but it is still needed by those bacteria for other purposes. [emoji3]

Yeah I should have been more clear that traces of phosphates are still necessary for the bacteria to grow but not for the denitrification process to occur. Good thing you are here to fix all our chemistry mistakes

 

[Factory909racer2]

The phosphate may not actually be low enough to limit denitrification, but I’d want to raise it anyway, and dosing it may be a good idea. [emoji3]

What do you do to raise it? I dont run GFO. I could cut back nopox maybe.

 

[Randy Holmes-Farley]

I’d dose a suitable phosphate material and see what happens. [emoji3]

 

[Factory909racer2]

I’d dose a suitable phosphate material and see what happens. [emoji3]

What do you feel is a suitable phosphate to dose? I have never had to dose phosphate.

 

[Randy Holmes-Farley]

A food grade sodium or potassium phosphate, or a hobby brand such as Brightwell Neophos.