High Phosphates and Zero Nitrates

[Drewb628]

I have a 170 gallon tank that is a few months old. Everything has been going smoothly but I have a large imbalance between nitrates and phosphates. My nitrates have trended down to 0 and now my phosphates have spiked way above the norm. I have read through a few forums on here with the same problem suggesting dosing nitrates so that it can be used to remove the phosphates.

Tank Specifics:
- protein skimmer with good output
- refugium with macro algae
- filter socks replaced 1-2 times a week
- Feeding: 1/2 cube of mysis shrimp once a day and TDO Chroma Boost pellets once a day (1x Foxface, 2 maroon clowns, 1 hawkfish, 3 cardinal fish, 1 file fish, 1 diamond goby, 1 midas blenny)


Levels:
Salinity: 1.026
Nitrate: 0
Phosphate: 0.22
Magnesium: 1350
Calcium: 440
Alkalinity 9.0

Is this something that will fix as the tank matures or will I have to does nitrates in the long term? Also is there something I am doing that is causing this imbalance? I would like to address it rather than dosing long term.

 

[Randy Holmes-Farley Verified Community Expert]

The phosphate is fine, IMO, and is within my recommended target range.

I’d feed more or dose N to bring up nitrate.

 

[Randy Holmes-Farley Verified Community Expert]

This has more discussion, including tank examples with far higher phosphate:

Randy’s Thoughts on Nutrient Target Ranges

Thoughts on Nutrient Target Ranges by Randy Holmes-Farley Almost nothing in the world of reef aquarium chemistry causes as much discussion as selecting and maintaining ranges for nitrate and phosphate. Some aquarists want low targets, some want...

www.reef2reef.com

 

[Drewb628]

This has more discussion, including tank examples with far higher phosphate:

Randy’s Thoughts on Nutrient Target Ranges

Thoughts on Nutrient Target Ranges by Randy Holmes-Farley Almost nothing in the world of reef aquarium chemistry causes as much discussion as selecting and maintaining ranges for nitrate and phosphate. Some aquarists want low targets, some want...

www.reef2reef.com

This is a very helpful, thank you!

As someone who upgraded from a smaller tank (and struggled with keeping nitrates in check) it's a nice change to hear I need to actually feed more and not less.

 

[EnterName]

Here is a link to an ammonia dosing recipe which works really nicely:

DIY Ammonia dosing for low nitrate systems

Some reef aquaria have chronic low nitrogen availability. One indicator is very low nitrate. Nitrate dosing is a fine remedy, but it is possible that ammonia dosing may be more beneficial for some organisms since ammonia can be energetically easier to assimilate than is nitrate. For this...

www.reef2reef.com

It's possible that phosphate uptake will increase once more nitrogen is available, but if phosphate keeps rising you can use granular ferric oxide (GFO) to reduce it effectively without having to rely on lots of water changes.

 

[exnisstech]

Feeding more didn't really help me. The ammonia dosing posted above worked very well. I saw better results than dosing sodium nitrate. I had chronically low N and P but finally almost 3 years later I don't have to dose either.