Trying to raise Nitrates

[reefwars]

stole this from RC:

Originally Posted by tmz

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

The redfeild ratio is rather useless as a guide other than to offer perspective on the general 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 seawater 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 bio available) 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 and or precipitants 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 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.

[Reefer Rob]

I think once a well set up tank is established our test kits for N and P will read zero anyway, so it is almost a waste of time to even use them. I never test for nitrate (after about 6 months) and test phosphate maybe every 2 or 3 months just to be sure.

Chasing magical numbers will only get you into trouble. Watch your corals and respond to their needs. If they start become too light add amino acid to increase available nitrate. If everything looks good, leave it alone.

My 2c, your results may vary

[Aquattro]

Originally Posted by Reefer Rob

Chasing magical numbers will only get you into trouble.

I think that sums it up well. I test NO3/PO4 maybe once a year. Test Ca 2 or 3 times. Check alk when my yellow monti turns grey. LEave it alone, watch the corals and change your water. Easy peasy.

[e46er]

I have pounds and pounds of KNO3 from my planted tank days I could give you some if you make the drive out to maple ridge

[Werbo]

Forget magical numbers. Especially with our hobby grade test kits.

The UNLS theory is that bacteria need some nitrogen to lower phosphate to zero. So nitrate is a limiting factor to lowering phosphate to zero in bacteria systems. This is why many biopellet users also employ GFO to get PO4 to ZERO. Simply put once nitrate levels reach 0 your PO4 will not come any lower if you are trying to reach UNLS by growing bacteria that is skimmed out.

Add amino acids (Zeovit or something similar) to feed corals and raise nitrates but it is also an added expense and time.

But as others have said judge by your corals response not magically numbers.

[reefwars]

a little reading as its gets complicated.

http://reefkeeping.com/issues/2006-08/cj/index.php

[Aquattro]

Originally Posted by reefwars

a little reading as its gets complicated.

That's when I stop reading. Feed fish, change water, clean skimmer. Done.

[gregzz4]

Guess I'll try the amino acids then, and go back to my normal fish food routine

Thanks all

[reefwars]

Originally Posted by gregzz4

Guess I'll try the amino acids then, and go back to my normal fish food routine

Thanks all

Greg what is it your trying to accomplish maybe we can help like Darryl said, a little input from some sound resources goes a long ways

[gregzz4]

I'm trying to get some life back in my SPS as some are too pale and growing slowly

I've cut my lighting down a bit and it's helping, but I'd like to improve them some more