Extremely high PO4 zero NO3

[Formulator]

As the title suggests, my phosphates seem to be out of control at 2.0 and I somehow have zero Nitrates. The tank was neglected for a couple years after my daughter was born and essentially went for 2 years with no water changes or detritus removal and very few times emptying the skimmate (it just kind of constantly trickled over the edge). The CUC died off, but I recently replenished it. Lost a few fish during that time and never found them so I assume they just decayed/were consumed by the tank. I’m not proud of any of this, but it is what it is. Honestly its a wonder that the Nitrate isn’t through the roof too.

Anyways, I’ve just “renovated” the tank and it is looking great again, but for the life of me, I can’t seem to get the phosphate levels to come down. I am still battling a bit of hair algae, but starting to get it under control with manual removal and many snails helping.

I’ve done multiple 20% water changes, siphoned out tons of detritus from the sand bed, and I’ve most recently run Phosguard in a reactor for 5 days and saw no change in PO4 from any of these things. I just changed the phosguard media out so will see if I can make a dent with that in a few more days. I will be starting up a large refugium this week with chaeto.

The tank is a 120g mixed reef with many (somehow) happy SPS, LPS, a couple leathers and a RBTA. Decent fish load with a blue tang, foxface, blue chromis, lyretail anthia, 2 clowns, cleaner wrasse, diamond goby, and a fairy wrasse. Also about 30 snails (turbo and trochus), a couple fighting conch, 10-15 hermits, and 2 cleaner shrimp. About 60% of the fish and inverts are new additions since the renovation over the last 6-8 weeks.

I run a 55 gallon sump with no mechanical filtration except filter socks I run on occasion if I notice water clarity issues, an octopus skimmer, carbon reactor, and recently a phosguard reactor. I have a RODI system with ATO. Also possibly noteworthy that I used to run ultra low nutrients with carbon dosing before the period of neglect.

Any suggestions for reducing PO4 this high and any clue how my Nitrate could be consistently zero still? Are they related?

Salinity: 1.026 (refractometer)
pH: 7.8-8.3 between day/night (Apex probe)
Temp: 78.2-78.8
Alk: 8.9 dKH (Salifert Kit)
Ca: 490 ppm (Salifert Kit)
Mg: 1290 ppm (Salifert Kit)
Nitrate: 0 ppm (Salifert Kit)
Phosphate: 2-3 ppm (Salifert Kit, between 1 and 3 on the color chart, closer to 3)

I know the Ca and Mg are a bit high, but thats what you get with Reef Crystals.

Thanks in advance for any suggestions you may have!

 

[Mechano]

Maybe try going the lanthanum route to lower phosphate and bring up the nitrate levels as nutrients are obviously way outta wack and you wanna end up with dinoflagellates

Don’t go crazy trying to lower it too fast for your phosphates, and also be slow adding nitrate as well as you don’t wanna shock anything.

I would suggest trying another test kit for the phos/nitrates as well to be sure.

Do you have a picture of your system today with white lights on only to share?

 

[Lavey29]

Agree with the above but if you don't dose your nitrates up then your phosphate will never come down.

 

[Mechano]

Agree with the above but if you don't dose your nitrates up then your phosphate will never come down.

I also agree with this statement. Adding nitrate brings down phosphate typically.
I am not a chemist , but search it up online here and there is a lot of info in this regard.

 

[Lavey29]

I also agree with this statement. Adding nitrate brings down phosphate typically.
I am not a chemist , but search it up online here and there is a lot of info in this regard.

I'm not a chemist either but for some reason in order to process phosphate the tank needs comparable nitrates. At least what I've learned in research.

 

[Randy Holmes-Farley]

Well, of course one can bring phosphate down with no nitrate when using a method like GFO or lanthanum or aluminum oxide, but I agree that making sure there is enough available N is important.

In addition to bring down phosphate, I'd either feed more, or dose one of sodium or calcium nitrate, or ammonium chloride or bicarbonate.

 

[Lavey29]

Well, of course one can bring phosphate down with no nitrate when using a method like GFO or lanthanum or aluminum oxide, but I agree that making sure there is enough available N is important.

In addition to bring down phosphate, I'd either feed more, or dose one of sodium or calcium nitrate, or ammonium chloride or bicarbonate.

Yes, I was referring to a natural tank process without chemical additives but didn't state it clearly in my post....thanks for clarifying

 

[Formulator]

Thank you all for the suggestions. I have been able to reduce the phosphates to slightly over 1.0 after 2 rounds of seachem’s phosguard media over about 8 days. I am still reading zero nitrates and have a suspicion the phosphates will come back up in a few days as the rock equilibrates with the water. I have ordered some sodium nitrate and plan to dose nitrates up with that. I will read up, but while we are here, any suggestions on a good target for NO3?

I honestly can’t believe I am going to dose nitrate… Am I imagining this or has there been a paradigm shift in just a few years since the last time I really dove into my tank chemistry and everyone seemed to be striving for ultra low nitrate levels?

 

[killer2001]

Amino acids can also be a way to introduce more nitrate into your system.

 

[radfly]

I would slowly dose a little ammonia, it will get converted to nitrate slowly and not upset the system. This will stabilize phosphate. Look into the foods you are feeding, because phosphate is added only by YOU, through feeding.

 

[Formulator]

I would slowly dose a little ammonia, it will get converted to nitrate slowly and not upset the system. This will stabilize phosphate. Look into the foods you are feeding, because phosphate is added only by YOU, through feeding.

Yes, I’m sure it is related to my feeding. I feed almost exclusively frozen mysis and spirulina plus a daily sheet of nori for my tang and foxface. Supplement with freeze dried cyclops and reef roids for the corals on occasion. Also give my RBTA a bite of cocktail shrimp about once/month. I don’t strain the frozen food but may need to start doing that.

 

[crazyfishmom]

Yes, I’m sure it is related to my feeding. I feed almost exclusively frozen mysis and spirulina plus a daily sheet of nori for my tang and foxface. Supplement with freeze dried cyclops and reef roids for the corals on occasion. Also give my RBTA a bite of cocktail shrimp about once/month. I don’t strain the frozen food but may need to start doing that.

Reef roids are a huge source of phosphate. To give you an idea on how bad: I have a 230 or so gallon system between rank and sump minus rocks and livestock. My PO4 was 0.04, I target fed using reef roids and tested after 16 hrs or so, my PO4 was at 0.6 (yes, not 0.06).

 

[Formulator]

Reef roids are a huge source of phosphate. To give you an idea on how bad: I have a 230 or so calling system between rank and sump minus rocks and livestock. My PO4 was 0.04, I target fed using reef roids and tested after 16 hrs or so, my PO4 was at 0.6 (yes, not 0.06).

Wow that is a big increase! I only feed roids about twice/month, but may have to skip them for a while…

 

[killer2001]

Spirulina is a big source of PO4 I've come to realize.

 

[crazyfishmom]

Wow that is a big increase! I only feed roids about twice/month, but may have to skip them for a while…

I couldn’t believe my eyes. Have repeated the experiment a couple of times now. It’s a huge jump every time. Currently trying to find Coral foods (besides aminos) that do not raise phosphates. Benepets benereef does the same.

 

[Randy Holmes-Farley]

I will read up, but while we are here, any suggestions on a good target for NO3?

I’d target 10 ppm nitrate.