Dosing Nitrate to reduce Phosphate

[der_wille_zur_macht]

andex, you might want to test for K as there is the potential it is limiting chaeto growth as well - read the last few pages of the stickied turf scrubber threads as some people relying on ATS are finding that dosing K allows more algae export and hence P can be brought closer to zero.

2hands, your ATS assumption is based on an "ideal" algae always being avaialble and ready to take over the screen - in practice I don't think this is true (see above comment ).

 

[Moser]

Zeostart3 test positive for Nitrates. According to a post on another forum that talks about Nitrate dosing.

And i agree, many may be doing it without knowing.

Hmm, Zeostart3 is a mix of carbon sources like VSV. Not sure why you should get a nitrate reading from it......
I was thinking more about Sponge Power....

Mo

 

[Fryman]

Honestly I think the theory is sound but I question the value of chasing 0.00 phosphate.

In my tank I measure 0.00 - 0.08 ppm phosphate (using hanna meter). I used to add GFO whenever it was above 0.04ppm, and that would always bring it down to 0.00ppm. Then I got lazy and stopped. Nothing changed. I still measure 0.00 - 0.08ppm phosphate. It seems to cycle slowly between those numbers over the course of a few weeks or so.

There's apparently some sort of internal cycle going on in my tank. Something happens when phos gets high that brings it down. Or maybe I've reached an equilibrium @ ~0.04 ppm and the perceived fluctuation is just measurement error. I'm not sure, but at the end of the day I haven't seen any difference on my livestock when the phos measures "high". The only time I saw an impact was when I added too much GFO & the level dropped rapidly (livestock did NOT like that). So I'm just not sure that maintaining exactly 0.00 or whatever number we decide is "optimal" matters as much as we think.

I also think people may falsely attribute a change to something they did. When I used to add GFO I assumed this was needed to bring down my phos, but then I found that if I do nothing it happens anyway. So what does the GFO do for me?

 

[Big E]

Honestly I think the theory is sound but I question the value of chasing 0.00 phosphate.

In my tank I measure 0.00 - 0.08 ppm phosphate (using hanna meter). I used to add GFO whenever it was above 0.04ppm, and that would always bring it down to 0.00ppm. Then I got lazy and stopped. Nothing changed. I still measure 0.00 - 0.08ppm phosphate. It seems to cycle slowly between those numbers over the course of a few weeks or so.

There's apparently some sort of internal cycle going on in my tank. Something happens when phos gets high that brings it down. Or maybe I've reached an equilibrium @ ~0.04 ppm and the perceived fluctuation is just measurement error. I'm not sure, but at the end of the day I haven't seen any difference on my livestock when the phos measures "high". The only time I saw an impact was when I added too much GFO & the level dropped rapidly (livestock did NOT like that). So I'm just not sure that maintaining exactly 0.00 or whatever number we decide is "optimal" matters as much as we think.

I also think people may falsely attribute a change to something they did. When I used to add GFO I assumed this was needed to bring down my phos, but then I found that if I do nothing it happens anyway. So what does the GFO do for me?

Yep..........chasing that number down to some mythical perfect water quality level is pointless. A number like that is a guideline. People would be better off getting in that range & let the corals tell them what's best. You can tell way more by really looking at your corals every day.

When you see good growth & color and algae is manageable that's when it's important to test. Then you can focus in on where your tanks balance & sweet spot is.

Most of the time when people focus on that number is when it's really high or they're having problems. Ten different things are done & one may be adding GFO. I would think more often than not, if husbasndry/export were improved you have changed your bacterial balance & the chemical control isn't needed.

GFO use gives you instant feedback on lower PO4 numbers on a meter, but the long term & more beneficial results take weeks to show up.

As far as there being a flucuation in the reading there can be hundreds of variables that effect that. Is the sample taken in the same spot everytime, same time of day, after a water change, or before or after some minor change? Those are just a few examples & then there's also the error of the meter...........it's not like those tubes are lab grade either & another 50 or so variables in the equipment & how the test was done or how much reagent got into the tube and on & on.

 

[swcc]

I believe the whole idea of phosphate control in aquariums was to help control algae...not necessarily for coral health. fresh water aquariums also look at phosphate control as well.

 

[der_wille_zur_macht]

Phosphate control is absolutely required for coral health. Elevated phosphate levels can inhibit calcification. There are many species of hermatypic corals commonly kept in modern reef aquariums that will simply not stay alive if phosphate levels are too high. Control of phosphate levels was one of the advances in the hobby over recent decades that allowed these corals to be kept without failing health.

That said, reaching true zero levels of phosphate is just as deadly which is why it is important to distringuish between levels not detectable via a given test method (the test shows zero but P is present in the water) vs. actually having NO phosphate in the water column. As I'm sure we're all aware, this threshold is very different depending on the method you're using to test. Luckily there are hobby-level testing methods that allow us to accurately show the levels present in natural seawater on coral reefs for phosphate - so we know what a reasonable target is, we have methods to test for that level, and we (clearly) have a variety of methods to control the level, both directly and indirectly.

 

[swcc]

Considering folks can't seem to get phosphate to zero testable for the most part I don't think zero in the water would ever be likely for anyone and thus really is not a true concern You can do all the skimming gfo dosing you want and your only gonna get so low. Interesting enough the Op is talking dosing N to reduce trace P and the last page has been how trace P is fine.... so why dose N again if P is already kept in a safe range?

 

[der_wille_zur_macht]

Based on surveying threads on this forum and anecdotal conversations with hobbyists I'd say it's somewhat common for people new to GFO or lanthanum to drop P too low by overdosing. It's certainly possible to actually reduce the level to effectively zero (i.e. low enough to cause harm) with many methods of P reduction/export - Just look for threads where people report damage to corals and other livestock after beginning an aggressive P remediation strategy.

I'm not sure what to make of your last few sentences. Clearly there are lots of aquariums in the world where P is larger than the hobbyist desires yet N is undetectable, which means this proposed method is still potentially valuable to some subset of the hobby even if you're arguing the OP's parameters are acceptable.

 

[swcc]

I would put that more as a sudden drastic change... drastic change to your bacteria and bad things happen. last few post are don't chase po4 numbers and that one person with his great growth sps with one ppm po4....

 

[andex23]

Andex23

I went to amazon and purchased 1 lb of NaNO3. It cost ~$10. It was 99.5% pure. I was thinking if I only add 0.1ppm nitrate per day the the amount of impurity should be close to nil. I have not started adding NaNO3 yet as I am still doing some research.

I think chaeto systems are perfect for nitrate addition. The chaeto needs more nitrate than we have and the LR and DSB is taking too much of it out.

I was also thinking if one had an ATS then one would need no additional nitrate because the more the ratio of N changes a different kind of algae will grow. Kind of self compensating.

I like you have chaeto. I would like collaborate with you on how to execute this. What do you think about 0.1 ppm per day?

I am going to start this method in the near future and will try to keep my results updated. Based on Der_wielle's post I will test for K first to ensure the other parameters are in line before I start dosing. My one thought is that if I can grow micro algae on glass now without an ATS, am I really K limited?

Depending on the results I may lean towards KNO3 instead of NaNO3.

My goal is not to eliminate P altogether as I know it is necessary for many coral functions. I want to reduce the amount of micro algae growth which is an indicator of excess phosphate. I think it is possible for cheato to out-compete for the phosphate in that situation and so dosing may help confirm which algae (macro/micro) will win the phosphate battle.

 

[swcc]

I am going to start this method in the near future and will try to keep my results updated. Based on Der_wielle's post I will test for K first to ensure the other parameters are in line before I start dosing. My one thought is that if I can grow micro algae on glass now without an ATS, am I really K limited?

Depending on the results I may lean towards KNO3 instead of NaNO3.

My goal is not to eliminate P altogether as I know it is necessary for many coral functions. I want to reduce the amount of micro algae growth which is an indicator of excess phosphate. I think it is possible for cheato to out-compete for the phosphate in that situation and so dosing may help confirm which algae (macro/micro) will win the phosphate battle.

If you can grow algae on the glass or anywhere you already have overly elevated nutrient levels in your tank and have an eutrophic tank... adding more nutrients is just going to make it worse...but...whatever. Evidently, I am crazy for suggesting that a high nutrient eutrophic tank does not need more nutrients but less. Thank god I am crazy though...my fish and coral love me for it.

 

[ormet]

Hmm, Zeostart3 is a mix of carbon sources like VSV. Not sure why you should get a nitrate reading from it......
I was thinking more about Sponge Power....

Mo

My theory? Mr pohl knows that you need a little bit of N to get rid of all Po4 using VSV ...

bundle it and get ZEOVit success.

Just guesswork, i have not tested Zeostart3 myself, a user on another forum reported this.

 

[mhucasey]

I have a heavily stocked SPS tank and feed 4-5 times a day with frozen food(Anthias piggies). I dose Vinegar and have never had measurable nitrates - but with my hanna I see PO4 values between .03 and .06. This has had an effect on the colors of the SPS.

Because of the imbalance, I have battled a bit of cyano on the sand and especially in the refugia. I have tried phosgard and the number would drop but not stay down, and changing out the phosgard is a bit of a pain.

I ordered some calcium nitrate - it was 3 bucks for a pound. I tested the water Friday morning getting a value of 0.06 for phosphate. I then mixed up a solution of calcium nitrate and added enough to bring nitrate up to 3ppm. 20 minutes later there was a mini bloom - slightly cloudy water and the skimmer went nuts with thick skimmate. The corals were happy happy during this.

I tested again late friday night, and low and behold - 0.00 on the hanna. Additionally during the day no new cyano, what was there died off, and in the refugia, it literally peeled up off the sand and floated to the surface.

Once I dial in a maintenance dose(if needed) i will just add the nitrate to my vinegar reservoir connected to my dosing pump.

For my 3 bucks i have enough to dose for about 2 years BTW.

 

[reefmutt]

I am no chemist but that sounds like a precipitation event..
What's the ph of calcium nitrate? Was there a change in your ph or alk after dosing?
Are you sure this doesn't precipitate po4 as opposed to raising no3 to help bacteria consume po4?
I'm curious because the cloudyness and the almost instant reduction of po4 seem to be more in line with products like dispo phos from coral shop that seem to remove the po4 from the water column but don't really do much about the source of the po4..
I'm wondering out loud here..

 

[mhucasey]

No change in pH other than slight lowering during the mini bloom(~-0.03pH units).

I made a solution of the calcium nitrate using 24g calcium nitrate with DI water to make 500ml. I added 50Ml of this solution to the sump. Once I saw the water become slightly cloudy, i looked at the skimmer and it was pulling dark gunk out. This skimmate is different than what I have been seeing with the vinegar dosing but is similar to what I saw a few months back when I was using biopellets. It was definitely a bacterial bloom.

Today, back to normal skimmate and no new cyano...Ill update as things develop

 

[reefmutt]

Hm.. Do bacterial blooms really happen that fast?
I wonder what concentration of calcium you get when you mix 26g of calcium nitrate with 500 ml water? See, chemistry not my forte..
It would seem that one could seriously effect one's calcium levels and perhaps ionic balance using this stuff on a regular basis..
Again, I'm thinking out loud because I'd consider using this stuff as well, if it really has such a positive effect on po4 in a no3 limited system..

 

[mhucasey]

The bloom might have been in process but not yet visible since I automatically dose 15ml vinegar 3 times a day and this was an hour or so after dose #1. I thought it was pretty quick myself but I am confident it was bacteria. I don't usually see anything more than the slightest cloudiness after vinegar dosing(just see this occasionally), usually followed by extremely clear water - and I don't see the action at the skimmer like I did.
The effect on calcium is inconsequential - according to the calculator 1ppm. I used the following calculator to generate a dose of 3ppm:
http://calc.petalphile.com/en/ Note that the calculator generates a value for calcium ppm when you plug in calcium nitrate but gives you the nitrate ppm as well in teh results.
I tested Phosphate today and once again 0.00ppm. My API test for Nitrate showed slight color above zero but was still below 5ppm. I normally have a yellow that is lighter than the "zero yellow". Yes I know that API tests are not the best, i only use the test for gross indications of any nitrate spiking.

I bought the Calcium nitrate at aquariumfertilizer.com

 

[Thales]

Phosphate control is absolutely required for coral health. Elevated phosphate levels can inhibit calcification. There are many species of hermatypic corals commonly kept in modern reef aquariums that will simply not stay alive if phosphate levels are too high. Control of phosphate levels was one of the advances in the hobby over recent decades that allowed these corals to be kept without failing health.

Do you have any references for the above and how high is too high? IIRC the last paper I read about it showed that levels of .5 really only resulted in less dense skeletons, but didn't otherwise impact overall health or growth.

 

[andex23]

The bloom might have been in process but not yet visible since I automatically dose 15ml vinegar 3 times a day and this was an hour or so after dose #1. I thought it was pretty quick myself but I am confident it was bacteria. I don't usually see anything more than the slightest cloudiness after vinegar dosing(just see this occasionally), usually followed by extremely clear water - and I don't see the action at the skimmer like I did.
The effect on calcium is inconsequential - according to the calculator 1ppm. I used the following calculator to generate a dose of 3ppm:
http://calc.petalphile.com/en/ Note that the calculator generates a value for calcium ppm when you plug in calcium nitrate but gives you the nitrate ppm as well in teh results.
I tested Phosphate today and once again 0.00ppm. My API test for Nitrate showed slight color above zero but was still below 5ppm. I normally have a yellow that is lighter than the "zero yellow". Yes I know that API tests are not the best, i only use the test for gross indications of any nitrate spiking.

I bought the Calcium nitrate at aquariumfertilizer.com

The other option is that you precipitated CA3(PO4)2. I am no genius, this comes from Randy in his phosphate article.

This could explain the 0.00 phosphate reading.

P.S. I love the calculator, I have KNO3 and will use it to begin my dosing.

Andrew

 

[reefmutt]

Yes, I tend to agree with this hypothesis.