Phosphate & Nitrate Locked on Zero - Massive Plus-NP Dosage?

[The0wn4g3]

So I have a 75 gallon mixed reef which was started in February. I've used Salifert tests kits since the beginning and have never read phosphate or Nitrate above zero.

Long story short, have been feeding like crazy (mysis, reefroids, phyto), turned the skimmer off, removed the filter sock, cut down on refugium lighting...still zero. Started dosing Tropic Marin Plus-NP at max dosage (3mL per day) for weeks, still zero.
I just received a Hannah phosphorus checker, and even it read zero!

So I took 1 Liter of RO water and added 1 mL of Plus-NP and the checker shows 32ppb [0.098ppm phosphate].

Would it be an absolutely terrible idea to do a single or several large doses in order to raise phosphate to 0.03ppm?

If my math is right, I have 90 gallons [341 Liter] of water then 1mL/L * 341L / 3.333 = 102mL should give me 0.03ppm.

Thoughts? Is this crazy? I'm getting desperate as my acros are starting to show significant stress and I believe it's due to lack of nutrients.

 

[Silentjay]

I'm having the same exact same issue. I setup my Waterbox 105.3 in March and have had nothing but zeroes for the last 2 months. Livestock seems fine aside from poor polyp extension on the SPS frags and all the Dinos populating the sand and rock. I finally got my phosphates to around .03 but Nitrates continue to be zero. I'm feeding the tank 4 times a day (2 cubes frozen, 2 doses of pellets and nori) and have recently started feeding coral 3 times a week. Not running a skimmer and reduced the refugium light to 5.5 hrs a night. Trying to go slow with the changes but thinking about dosing Stump Remover or something if I go another few days without nitrates. Also, ordered another Nitrate test kit to double check my readings.

 

[The0wn4g3]

I'm having the same exact same issue. I setup my Waterbox 105.3 in March and have had nothing but zeroes for the last 2 months. Livestock seems fine aside from poor polyp extension on the SPS frags and all the Dinos populating the sand and rock. I finally got my phosphates to around .03 but Nitrates continue to be zero. I'm feeding the tank 4 times a day (2 cubes frozen, 2 doses of pellets and nori) and have recently started feeding coral 3 times a week. Not running a skimmer and reduced the refugium light to 5.5 hrs a night. Trying to go slow with the changes but thinking about dosing Stump Remover or something if I go another few days without nitrates. Also, ordered another Nitrate test kit to double check my readings.

I added (2) 10mL doses of Plus-NP last night 1 hour apart. I then waited an hour after the second dose and phosphate measured as 7ppb [0.021ppm]. Looks like the math didn't hold up, but I was lucky enough to get close to 0.03ppm.
I'm going to wait 24 hours (9pm tonight) and re-test.
Nitrate still tests as zero...

 

[Jeff Jarry reef]

I also have a 90 gallon SPS dominant and my P and N was staying at zero I dosed ATI N and P it helped some. So I add some more fish now it stays balanced pretty good.

 

[The0wn4g3]

Just as an update, ran another phosphorus test tonight and it came back dead zero. Added another 20 mL of Plus-NP.

 

[The0wn4g3]

Tested phosphate again this evening, still zero... I'm going to dose 30mL of Plus-NP over the course of this evening if I have enough.

 

[Randy Holmes-Farley Verified Community Expert]

Tested phosphate again this evening, still zero... I'm going to dose 30mL of Plus-NP over the course of this evening if I have enough.

You might want to switch to a DIY product where you know the potency.

Regardless, it takes a lot to raise phosphate since much of it will bind to rock and sand.

 

[The0wn4g3]

You might want to switch to a DIY product where you know the potency.

Regardless, it takes a lot to raise phosphate since much of it will bind to rock and sand.

I've bought a bottle of Brightwell Neophos and Neonitro. Their instructions seem a bit more scientific.
So is that the leading theory these days, that the rock is absorbing the phosphate?

 

[The0wn4g3]

You might want to switch to a DIY product where you know the potency.

Regardless, it takes a lot to raise phosphate since much of it will bind to rock and sand.

Added 5.7mL of Neophos per instructions to reach 0.02ppmearlier, waited 2 hours and test came back 0.018ppm so that's good!

Is there anyway to estimate the uptake time of the rock/sand or and I best just waiting 25 hours and retesting?

I'm afraid at this rate it may take forever to get things in order and cost many tests...

 

[Randy Holmes-Farley Verified Community Expert]

I've bought a bottle of Brightwell Neophos and Neonitro. Their instructions seem a bit more scientific.
So is that the leading theory these days, that the rock is absorbing the phosphate?

Phosphate binding to rock is not a theory. It is an easily demonstrated fact.

But the amount in your cause can only be determined experimentally. Just dose until you see it rise.

 

[The0wn4g3]

Phosphate binding to rock is not a theory. It is an easily demonstrated fact.

But the amount in your cause can only be determined experimentally. Just dose until you see it rise.

Can rock also absorb nitrate? Because I can dose nitrate, get a reading of 5ppm, and 4 hours later it's 0. That's seems awefully quick?

 

[Crustaceon]

Skimmer, enough live rock, feed sparingly (1 cube daily for every 50 gallons of appropriately stocked tank), occasional small water change (5% per week is fine, just swish the sand). Keep it simple and things get really easy.

 

[Randy Holmes-Farley Verified Community Expert]

Can rock also absorb nitrate? Because I can dose nitrate, get a reading of 5ppm, and 4 hours later it's 0. That's seems awefully quick?

No. It must have been consumed by organisms.

There may be old/dead organic matter than can degrade and eventually release nitrate, but calcium carbonate does not directly bind ammonia/nitrite/nitrate.