Dosing Nitrate to reduce Phosphate

steve9, what kind of update do you want?

In a tank where nutrient reduction is accomplished by bacteria export using organic carbon dosing and skimming sometimes no3 is a limiting factor. Dosing Nano3 or Kno3 is a proven method to remedy that.
 
Ive used Calcium Nitrate to keep my tank nitrate level above zero and preferably between 2-4 for about 6- 8 months now. If you are carbon dosing and keep finding yourself Nitrate limited it is one way to remedy that. I found out one reason that my tank kept getting out of balance with phosphates rising was because of Garlic additive of all things.

I add liquid garlic extract to my thawed mysis and allow them to marinate for about an hour before rinsing. With all honesty my rinsing was minimal before I found out that garlic is one of the foods doctors recommend for people who are phosphorus deficient! I add garlic because it eliminates finicky eaters(even my mandarin even eats mysis) and it *MAY* have some beneficial anti parasitical effects. I do a better job rinsing frozen food now.

The other (possible) source I found was my RO/DI unit - City water here in Oceanside Ca is absolutely horrible and it eats up DI resin very quickly(TDS for city water is 480-580!). I need to change my Cartridges and DI resin on the order of every 2.5 months or the TDS of the DI creeps up.

For those who say "just use GFO", I have tried GFO in the past and have lost clams because of it. Using enough GFO for my tank to keep the phosphate levels low leached too much iron, even with rinsing the GFO thoroughly. Within hours of adding it, I have clams pinching their mantles and in one case full clam meltdown within 12 hours of addition. Nothing else is changed when these events occur so I feel confident that the GFO is the culprit.

The Calcium Nitrate that I use was $3.00 for a pound. That pound will last me years...
 
I got some calcium nitrate can i mix it with vinegar
any body have a though on it.
Seems like a safe mix but im no chemist.
 
Yes, I was mixing the Calcium Nitrate with vinegar so that my daily dose of vinegar was adding about .75 ppm Nitrate per day. The Calcium Nitrate granules dissolve very nicely in vinegar and Vinegar's acidity keeps the solution from growing bacteria.
 
Interesting thread . Most have done a good job getting past some of the nonsense and irritation and name calling and stayed on point.

A few comments to consider:



It's certainly seems counterintuitive to dose nitrate or another nitrogen source but it may make sense.

The redfiled ratio is rather useless as a guide other than to offer perspective on the genral en masse proportions of carbon(C)106:N) 16: 1 P in ocean plankton. Organisms may approximate those levels but some including some bacteria vary significantly . Even if food put in the tank is close to those proportions, the activity in the tank may not use them in those proportions. All in all, trying to use the redfield ratio to obtain a generalized optimal N to P ratio seems convoluted. Using tank levels of N and P vs natural seawaer levels seems smarter and more direct.

To clarify the idea as to why dosing N might be necessary, a brief look at the three major nutrients coming in and going out of the bio available mix in the tank may be helpful

Organic carbon coming in for the most part with foods can be used for energy or sunk in refractory( non bioavailable) organics like humic and fulvic acids ;some may also be contributed by photosynthesis. So, the amount coming into the tank is not really the bio available amount in the tank.
In many tanks it seems there is a shortfall as N and P levels climb. If there was enough organic C the bacteria would use up the N and P too and tank levels would approximate nsw levels ( PO4 ca .005ppm and NO3ca. 0.2ppm) more often than they do. This imbalance is the basis for organic carbon dosing( vinegar, vodka, pellets, sugar, etc)
Unfortunately, hobby level measurement of organic carbon is not possible. Even high level analyses with $ 50 K analyzers don't really tell you what organics are present and whether they are bio available. So, we use No3 and PO4 as sort of a surrogate measure for nutrients, often ignoring organic carbon.

The proportion of N in and N out varies vis a vie the proportion of P in and P out too. The bacteria , consume C,N and P for food( ie, they assimilate them) and in turn are exported primarily by skimming . Even if we assume they have a perfect 116C to16Nto1 P biomass and the food into the tank also has these exact proportions,more N will be exported than P.
Anaerobic activity where the bacteria use NO3 for oxygen when free oxygen is used up exports extra N . NO3 is reduced to N as the oxygen is taken ;some of the N which binds to other N forming N2 which bubbles out into the atmosphere. How much of this occurs is variable from tank to tank but it does deplete nitrogen in addition to the nitrogen assimilated by the bacteria as biomass;there is no other such exit for P .
This is why many use gfo or other adsorbents for PO4 along with organic carbon dosing.

Sometimes, N levels at 0 may induce some coral paleness, perhaps from an N deficiency for the zooxanthelae or teh coral itself. Some think adding extra N via sodium nitrate or calcium nitrate will remedy that and also help the bacteria to reduce more P. Very plausible positions,imo. Some ,including me prefer to add extra N via aspartic acid and amino acid which also adds some organic carbon.
 
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Sometimes, N levels at 0 may induce some coral paleness, perhaps from an N deficiency for the zooxanthelae or the coral itself. Some think adding extra N via sodium nitrate or calcium nitrate will remedy that and also help the bacteria to reduce more P. Very plausible positions,imo. Some ,including me prefer to add extra N via aspartic acid and amino acid which also adds some organic carbon.

Thanks for the summary.

Could you please specify exactly what you prefer to use instead to of sodium nitrate, calcium nitrate or potassium nitrate and why? This would be a big help.
 
The Redfield ration has been touched on but then the significance of it actually overlooked.
Wether the ratio is 16:1 or 20:1 or anything in between is actually of little significance.

Fully understanding the minute details of the fate of nutrients is in my opinion something that is better left to those with more controlled conditions than an average aquarium can hope to offer.

Here is a fact many will be aware of: Phosphate is used as a preservative in dried fish food, human food and many foods in between! If in doubt read the labels, sodium phosphate, calcium phosphate, aluminium phosphate the list goes on! "But I only feed frozen food" I hear you yelling!
Well, I cannot speak for the frozen food manufacturers and indeed adding phosphate to a frozen product would seem illogical, however I bet whatever we are feeding has very often a gut full of high phosphate dried food! What I am trying to explain is that whatever we do, us aquarists add phosphate in a ratio far different to that discovered by Redfield. The consequence is that it cannot be consumed even in a perfect aquarium. Read Randy Farley Homes article on levels of phosphate for those that are interested or skeptical of me and i urge skepticism here!: http://www.advancedaquarist.com/2012/3/chemistry

This is the reason we must always find ways of exporting or binding phosphate even in a perfect aquaria, kalkwasser and GFO seem to be the best we have and work perfectly well for most!

Nitrate is a nutrient, only some more skilled and diligent aquarists will maintain at undetectable levels in the long term. I myself have been periodically adding a potassium nitrate solution for the last year and although I cannot obiviously offer any scientifically published data I very rarely change GFO, but I do use kalk have virtually undetectable phosphate levels and very many happy SPS corals that I often frag, no complaints over growth rates and coloration under 20000k and led combo.

Carbonate, Calcium, Carbon, Nitrate and phosphate amongst a few others in the correct balance are essential to coral vitality. These beautiful creatures have been created for an environment where phosphate appears to be the limiting nutrient (please google for papers there are many out there!).

We focus so much attention on Calcium and alkalinity requirements and maintaining low phosphates but since few can obtain growth that matches input of nitrate its addition is neglected.
For those that can maintain a balanced environment where input equals growth, it is my humble opinion that nitrate is often a significant growth limiting factor in a healthy aquarium its addition will drive phosphates to undetectable and possibly more natural where is can possibly take its more natural "limiting nutrient" title.... Until feed time that is! :)

Aaroz
 
Herringfish,

I'm not sure it matters a whole lot but as requested this is is my thinking:

Potassium nitrate(KNO3) adds potassium I might not need or want. I would use it if I measured and needed more potassium.

Calcium nitrate(CaNO3) adds calcium which I'd rather add in normal doses balanced with carbonate alkalinity.

Sodium nitrate(NaNO3) adds sodium but I don't care about that as much as the calcium or potassium since there is so much sodium in the water(10,500ppm) any small addition won't affect ion ratios very much at all and will level out with water changes . I've tried it.

Aspartic acid contains nitrogen and organic carbon in the form of an essential acidic ammino acid that living things incuding corals use . I account for the carbon part by reducing the vodka dose to off set the extra carbon. I use L aspartic acid from I herb .com,an online health food vendor ,ca $6 for 250 grams.
It only takes 4 grams 2x per week for 650 gallons to get N where I want it 0.5 to 1ppm . I'm still observing it since I started it just 2 weeks ago. Sps coral color seems to have gotten richer and lps seem fuller but I may just be seeing what I want to see.

I've been dosing vodka and vinegar for organic carbon over 5 years with very good results. in keeping NO3 and PO4 low. Sugar even in small amounts caused coral browning and some recession. There is at least one study linking excess glucose to coral mortality. So, I don't use any sugar anymore.
 
Among others,

Zedar Shows that it works short and long term.
and
TMZ Cutting through the non-since, getting specific and making it simple.

Thank you all.
 
Estimations of the Redfield ratio vs actual input ratio to an "ideal system" is of fundamental importance since we imbalance this input almost every day when we reach for the preserved food.

In a utopian aquarium where input = growth we would have no need for phosphate remediation via GFO or whatever we use. Obviously such an aquarium rarely exists.

Since phosphate almost always finds its cunning little way into a system and eventually the result is a snowball of death algae and low biological calcification, dosing Nitrate into a good growing feef with undetectable nitrates is far more logical AND quantifiable than "trace elementsm, molybdenum, iodine"..... the comical list goes on!

For those worried about imbalancing K levels when dosing KNO3 can i suggest Sodium Nitrate over Calcium nitrate

See if you add Calcium Nitrate theoretically one would slowly raise calcium values and this would need to eventually off set with the addition of sodium carbonate /bicarb depending on water changes.



Aaroz
 
The amount of calcium added with calcium nitrate is minuscule compared to normal seawater calcium concentrations. This is because the amount of nitrate added with the calcium nitrate is very small, only enough to pull the system up from undetectable to 1 or 2 ppm. For every 3 ppm nitrate you are adding 1ppm calcium - In the context of a reef that is nothing.

Pretty much the same thing goes for sodium Nitrate or Potassium nitrate.

Play around with the numbers yourself:
http://calc.petalphile.com/en/
 
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