High Nitrates / Low Phosphates

[dzuckerm]

Hi Everyone!

My 250 gallon (with 50 gallon sump) peninsula has been up and running for 8 months. Went through the whole ugly / dinos phase 3-4 months ago when nitrates / phosphates were both at zero. I increased bioload and started feeding twice daily (mostly frozen, some flakes) and finally got detectable nitrates and phosphates and dinos went away. Since then, nitrates have been trending up (now up to 42) but phosphates remain low (0.02). I have since turned my skimmer back on, added a refugium (although chaeto not doing well) and continues to use my reefmat. The only thing I dose is All For Reef. I have a tiny amount of hair algae on spots where direct sunlight hits the tank, but its very minimal. Fish are thriving, soft corals and LPS are doing OK. SPS are not doing well (some have died, others just arent growing). I do weekly 15% water changes. The only thing I dose is All For Reef.

My current levels: Salinity 1.026, pH 8.3, alk 9.3, Calcium 500, Mg 1400, Nitrates 42, Phospates 0.02.

Im concerned about the nitrate/phos imbalance and the risk of future nuissance algae.

Im thinking to start dosing neophos to raise the phosphates up to 0.1? I've read that bringing up the phos could bring down the nitrates?

If not (ie, if the phos goes up but nitrates stay high) Im thinking to start dosing NoPox with the goal of sustaining nitrates around 20s and phos around 0.1?

Am I overreacting / chasing numbers unnecessarily? or am I rightfully concerned about my high nitrate levels and nitrate/phos imbalance? and I am rightfully concerned, is my plan a good one?

Thanks so much!

 

[killer2001]

You may be bottoming out on phosphate at 0.02 which can cause the nitrates to rise. Bumping up to 0.1 sounds like a fine idea, something that I would do personally if it were me. There are DIY phosphate recipes from Randy you can use to save money instead of using NeoPhos.

 

[Pistondog]

Bring up the po4. Feed some reef roids 2 or 3 times a week.
Let things stabilize in your new tank. Turning on the skimmer may be enough to reduce nitrates.

 

[Randy Holmes-Farley]

Hi Everyone!

My 250 gallon (with 50 gallon sump) peninsula has been up and running for 8 months. Went through the whole ugly / dinos phase 3-4 months ago when nitrates / phosphates were both at zero. I increased bioload and started feeding twice daily (mostly frozen, some flakes) and finally got detectable nitrates and phosphates and dinos went away. Since then, nitrates have been trending up (now up to 42) but phosphates remain low (0.02). I have since turned my skimmer back on, added a refugium (although chaeto not doing well) and continues to use my reefmat. The only thing I dose is All For Reef. I have a tiny amount of hair algae on spots where direct sunlight hits the tank, but its very minimal. Fish are thriving, soft corals and LPS are doing OK. SPS are not doing well (some have died, others just arent growing). I do weekly 15% water changes. The only thing I dose is All For Reef.

My current levels: Salinity 1.026, pH 8.3, alk 9.3, Calcium 500, Mg 1400, Nitrates 42, Phospates 0.02.

Im concerned about the nitrate/phos imbalance and the risk of future nuissance algae.

Im thinking to start dosing neophos to raise the phosphates up to 0.1? I've read that bringing up the phos could bring down the nitrates?

If not (ie, if the phos goes up but nitrates stay high) Im thinking to start dosing NoPox with the goal of sustaining nitrates around 20s and phos around 0.1?

Am I overreacting / chasing numbers unnecessarily? or am I rightfully concerned about my high nitrate levels and nitrate/phos imbalance? and I am rightfully concerned, is my plan a good one?

Thanks so much!

I do not believe the concept that N/P ratio imbalances lead to algae problems, but I'd watch the phosphate to be sure it does not get too low, and dose it if need be. It is at the bottom of my recommended range right now.

Organic carbon dosing is a fine approach to reduce nitrate primarily.

If you do not yet have the neophos, I'd recommend food grade sodium phosphate for dosing. It is less expensive and carries a purity assurance.

 

[UMALUM]

Let it happen on its own. Trust me it will. Your tank is still relatively young and I'm guessing it was a dry rock start so just feed normally and it will balance. Remember it's alot easier to add them then get rid of them.

 

[dzuckerm]

I do not believe the concept that N/P ratio imbalances lead to algae problems, but I'd watch the phosphate to be sure it does not get too low, and dose it if need be. It is at the bottom of my recommended range right now.

Organic carbon dosing is a fine approach to reduce nitrate primarily.

If you do not yet have the neophos, I'd recommend food grade sodium phosphate for dosing. It is less expensive and carries a purity assurance.

thanks so much! So I will proceed with dosing phosphate with the goal of increasing it to approx 0.1. Any concern about the nitrates in the 40s (and continuing to rise slowly) despite protein skimmer / refugium / weekly 15% water changes and only daily feedings? If they remain elevated or rising despite increased phosphates should I think about carbon dosing (using something like Nopox)?

 

[dzuckerm]

Bring up the po4. Feed some reef roids 2 or 3 times a week.
Let things stabilize in your new tank. Turning on the skimmer may be enough to reduce nitrates.

Im just concerned about the nitrates going up even higher if i fed reef roids that frequently? Theyre slowing risking as is (despite the skimmer running, reefmat, addition of fuge, weekly 15% water changes, reduction in fish feeding to daily)

 

[Pistondog]

Im just concerned about the nitrates going up even higher if i fed reef roids that frequently? Theyre slowing risking as is (despite the skimmer running, reefmat, addition of fuge, weekly 15% water changes, reduction in fish feeding to daily)

Ime, reef roids raise phosphate mostly.

 

[Randy Holmes-Farley]

thanks so much! So I will proceed with dosing phosphate with the goal of increasing it to approx 0.1. Any concern about the nitrates in the 40s (and continuing to rise slowly) despite protein skimmer / refugium / weekly 15% water changes and only daily feedings? If they remain elevated or rising despite increased phosphates should I think about carbon dosing (using something like Nopox)?

There are some great tanks at 100 ppm nitrate, and some folks who believe their tanks do not do as well at 40 ppm as it would at 10 ppm or less.

I'd personally keep it from rising more, and might use a slow method of reducing it, like growing macroalgae or organic carbon dosing.

 

[Ironfish]

There are some great tanks at 100 ppm nitrate, and some folks who believe their tanks do not do as well at 40 ppm as it would at 10 ppm or less.

I'd personally keep it from rising more, and might use a slow method of reducing it, like growing macroalgae or organic carbon dosing.

I have a similar issue in my tank.
260gal
Tank started July 2023 but I transferred water, rock, fish and corals (no sand) from my previous 100gal tank.
Nitrates stay in the 25 to 35 range (moving up between water changes)
Phosphate stays below 0.1 bc im using Rowaphos. If im lazy at chaging the media it goes up to 0.2.

You mentioned growing macroalgae.
What about microalgae in an Algae Scrubber?
I have an IceCap AGR400 Pro and it just doesn't grow much. There's no algae to harvest so I'm not really exporting any nutrient.

 

[Ironfish]

There are some great tanks at 100 ppm nitrate, and some folks who believe their tanks do not do as well at 40 ppm as it would at 10 ppm or less.

I'd personally keep it from rising more, and might use a slow method of reducing it, like growing macroalgae or organic carbon dosing.

I have a similar issue in my tank.
260gal
Tank started July 2023 but I transferred water, rock, fish and corals (no sand) from my previous 100gal tank.
Nitrates stay in the 25 to 35 range (moving up between water changes)
Phosphate stays below 0.1 bc im using Rowaphos. If im lazy at chaging the media it goes up to 0.2.

You mentioned growing macroalgae.
What about microalgae in an Algae Scrubber?
I have an IceCap AGR400 Pro and it just doesn't grow much. There's no algae to harvest so I'm not really exporting any nutrient.

 

[Randy Holmes-Farley]

I have a similar issue in my tank.
260gal
Tank started July 2023 but I transferred water, rock, fish and corals (no sand) from my previous 100gal tank.
Nitrates stay in the 25 to 35 range (moving up between water changes)
Phosphate stays below 0.1 bc im using Rowaphos. If im lazy at chaging the media it goes up to 0.2.

You mentioned growing macroalgae.
What about microalgae in an Algae Scrubber?
I have an IceCap AGR400 Pro and it just doesn't grow much. There's no algae to harvest so I'm not really exporting any nutrient.

An algae scrubber can certainly be a fine way to export Na nd P, but I do not know the efficiency of any particular unit.