0 Phosphates

[cillam]

Hello i am fairly new to the hobby and started back in early June so my tank is about 4 months old. I was not happy with my nitrate levels so i started carbon dosing vodka to lower them and for around the first 3 weeks i was noticing them go down and then they did not seem to go down any more, so i tested my phosphates with he API phosphate kit, and quickly realized it was useless as the smallest reading is .25ppm. So i bought a Salifert phosphate kit and it came back showing 0 even when doubling the reagents.

I then bought some brightwell neophos which i have now been dosing daily for a week but every time i test it comes back with 0, the Salifert test should be able to detect phosphates at .03ppm. I really don't want dinos, and carbon dosing does not seem to help with no phosphates so i have stopped with the carbon dosing when i noticed i had no phosphates around a week and a half ago.

my tank is a 60 gallon display with a 20 gallon sump and when taking into account water displacement i have around 65 gallons of water in the system, I have no major algae in the tank which could be absorbing the phosphates, and as far as nutrient removal just a filter sock which i have not replaced in a week, a protein skimmer, a refugium with cheato and a bag of activated carbon.

I was wondering if having the bag of activated carbon in the sump is stripping the phosphates away when dosing and that is why i am not seeing any phosphates.

Any advice or suggestions are appreciated.

 

[EeyoreIsMySpiritAnimal]

Activated carbon does not remove phosphates. This is an example of the negative side of carbon dosing in a new tank. New tanks are unstable and will have varying nutrient levels as the different bacteria, archaea, and algae come and go. The best remedy for high nitrates is a water change.

 

[EeyoreIsMySpiritAnimal]

What are your current nitrate and phosphate levels?

 

[Fernthereefer]

If I have to guess ypu used dry rock to start your reef. They will absorb PO4 in the first year(s) depending how much you have.

To avoid bottoming it you can dose it (I did). However, the rocks will start leaching PO4 with time so beware. Keep a close eye.


Good luck

 

[cillam]

What are your current nitrate and phosphate levels?

Nitrates are around 50ppm phosphates still showing 0

 

[cillam]

If I have to guess ypu used dry rock to start your reef. They will absorb PO4 in the first year(s) depending how much you have.

To avoid bottoming it you can dose it (I did). However, the rocks will start leaching PO4 with time so beware. Keep a close eye.


Good luck

Yes i used dry rock and live sand. I was thinking maybe the rock is absorbing some of the phosphates but figured after a week i would be showing something.

 

[EeyoreIsMySpiritAnimal]

Nitrates are around 50ppm phosphates still showing 0

Change your filter sock - if it's been there a week it might be contributing to the nitrates.

 

[Randy Holmes-Farley]

With nitrate high and phosphate undetectable, I’d dose sodium phosphate. It is cheap and easy.

 

[jda]

Do you have a tool like a Hannah Ultra Low to accurately detect low phosphate? Color changing test kits are not accurate enough to chase this, IMO.

The phosphate that you are adding is likely binding to aragonite. As more bind, the tank level will rise. Again, don't let it rise too much with a color changing test kit because it can be hard to remove later.