Nitrates are BAD...no no no they are GOOD!! Wait, What?!?!

[Tjm23slo]

I learned the hard way 0 Nitrate and 0 Phosphate can lead to beaching corals and Dinoflagellates.

Added both as part of a recovery process and color came back to the corals. Mine are too high right now but on purpose as i fight the the Dinos. Otherwise I will shoot for <=0.1 PO4 and <=20 NO3

 

[Taylor]

I installed an ATS (diy) a couple of months ago and it was very productive within the first two weeks. I did not test regulary as I should have. But with consistent alk @8dkh, the nitrates went from 5+ppm to undetectable and phos went from .06 to .01/.02 in those 6 or so weeks. I was lighting my ATS for a very long period. The effect of this was my bird's-nest coral tip burning/bleaching and brown cyano took over the tips of firstk the frags and then the colony. Since stopping skimming and tuning the ATS to nearly off, my nutrients are back to where they were when the birdsnest was growing and the brown slime is minimal and I'm hoping for recovery soon. No other corals, sand or rock were really affected. I was blowing the birdsnest off 4-5 times a day, now it's just once.

 

[vetteguy53081]

I will accept nitrate, But at a low level. I quit fighting any levels other than Ammonia and it has paid off. Doesn't both corals/fish one bit probably because I quit chasing the numbers a long time ago

 

[ca1ore]

The trouble with these kinds of anecdotes is whether absolute levels are problematic or is it just the impact of changing the water chemistry that the corals react badly to. I’ve grown corals of all shapes and sizes when nitrates and phosphates were undetectable (to hobby grade test kits) and when they were most definately detectable. I do find that growth slows above about 0.1 phosphate, but color improves. Nitrates seem to have no material affect.

I think the broad goal should be to balance input with export, and maintain levels that are not too encouraging of pest algae. For me that’s nitrates below 20 and phosphates below 0.1. Not a great picture, but here’s my 450 with over 125 fish and many large coral colonies.

 

[Dondante]

I'm coming off of a 10 year hiatus. I've been keeping SW and reef tanks for 20+ years. It was a surprise to me that it has shifted from where it once was(no nitrates and no phosphates.)

Which is a good thing. Man, I spent so much time chasing those numbers.

 

[Rick.45cal]

I LOVE NO3 and I will even go so far as to say I love PO4! I feed both to my reef tank when it wants to be close to 0 on either one. I’m currently dosing PO4, been dosing for a couple months now to bring my tank up, it had fallen to near undetectable levels. I like to have 5-10ppm of NO3 and 0.12ppm PO4. My tank just seems to really thrive there. I think there’s a stigma attached to NO3 and PO4 like they are evil. Honestly I think GFO is evil and has probably killed more corals than NO3 or PO4 combined. That’s for another thread though. (I 100% agree with the high input, high output philosophy in reefing).

Proof is in the pudding...
Alk 9.5ppm
NO3 7.5ppm
PO4 0.12ppm

 

[Mark Gray]

I am pretty new to SPS but for everything else I have never had nitrate hurt anything. I have had fish only tanks with really high nitrate nothing effected. Now I have added a fuge and I struggle to keep nitrate up.

 

[Kit_Kat]

I don’t worry to much about nitrates. They mostly stay 3-5. I worry more about phosphates.

 

[biophilia]

What often gets lost in the discussion is limiting nutrients. NO3 being 0.5ppm or 5ppm or 50ppm really means nothing on its own. Clearly corals need some dissolved inorganic nitrogen as either ammonium or nitrate, as the presence of DIN has been shown in the literature over and over again to increase growth rates in all sorts of corals. The same goes for PO4 up to a point. The reality is people with success at high levels probably have another limiting nutrient in their tanks keeping nuisance algae at bay and those with success only at lower levels may not. Or just a lot of herbivores. It's important to remember that wild reefs are only not choked out by algae because a ton of herbivores graze on them all day long.

Nitrates aren't just not bad, they're essential. The carbon compounds released to the coral via photosynthate contain almost no nitrogen (with the exception of a super tiny amount from amino acids) which basically means photosynthesis alone has been shown in the literature to only be capable of supporting basic metabolic needs for the coral host. Growth and overall health simply requires nitrogen -- either as inorganic nitrogen or organic nitrogen via food capture (Falkowski et al. 1984). Either way is going to provide some NO3 in the water column for the corals so it's more or less true to just say "nitrates are good".

 

[Gary Inwood]

I have enjoyed reading this and i do agree with everyone, because all reef tanks are not equal but in saying that i'm going to shock you all by telling you all my Nitrates are 70 ppm and above and my reef is loving it.
KH 10.1
Ca 430
Mg 1400
pH 8.1

I have no algae in my DT and my cheato is growing like mad and my fish and coral are all healthy

 

[stevieduk]

nitrates are plant food,---algae inside coral is a plant,--nitrates feed coral

 

[FishyDP]

Right now I am comfortable around the 20 ppm range, but am keeping softies and lps only, in a 125g system. I am moving to a 180g system and will be adding my first sps. I anticipate more of a balancing act with nitrates with a full mixed reef, and will be shooting for the 10 ppm range. I have also read that most corals do need some level of nitrate, so I would not be comfortable at 0 ppm personally..

 

[Amps Reef Life]

I am to keep my reefs around 2-5 nitrates but no more than 5. It's a good thing but high amounts can be a bad thing.

 

[Salty Irishman]

Definitely in the camp of keeping detectable levels of both in my reef. After years of doing all I could to keep the levels ND and having corals simply survive rather than flourish, I was then plagued with dino's for my efforts, by which nothing has taken me to the brink of giving up the hobby like those did. And after months of trying all I had learned about the battle and not working I stumbled onto another thread and gave it a try. The premise was to get both values (N03 & P04) up feeding the beneficial bacteria and having them out-compete the dino's whereby eliminating them, and it worked like a dream! As a bonus, all of my corals have grown and colored up exponentially! All of my reef bugs came back and things are looking better than they have in quite a while. I can only conclude that I was starving everything with both levels at zero. Currently, I'm still dosing both and able to keep consistent values around: N03 = .30 and P04 = .03 The dreaded GHA (which is why we all decided to run zero on these values when it's a natural part of the evolution of the reef) has returned (for which I've never been so happy to see) bringing me literally full circle. The reef janitors are now very happy and keeping that under control nicely! So long term I'm currently working on building up the fish numbers in hopes to one day stop dosing N03 & P04 and let the fish poop take over!

 

[Salty Irishman]

I learned the hard way 0 Nitrate and 0 Phosphate can lead to beaching corals and Dinoflagellates.

Added both as part of a recovery process and color came back to the corals. Mine are too high right now but on purpose as i fight the the Dinos. Otherwise I will shoot for <=0.1 PO4 and <=20 NO3

+1. Haven’t had them go high on me but def cured the dreaded Dino outbreak I experienced and am still dosing daily to keep those levels up.

 

[MabuyaQ]

Nitrate readings are neither good nor bad, high or low. They are part of a nutrient balance game. If you have low nitrates because it is fueling problematic algae then that is bad. If you have high nitrates but your coral are healthy and colorful then everything is good. If you have low nitrates because you don't add enough nutrition to your tank, that is bad. If you have high nitrate because of decaying waste in your tank that isn't being consumed, that is bad.
Ideally, we will be importing and exporting nutrients at the same rate. What we read in the water is the lag between them being produced and consumed. Since everyone has different factors that impact the import and export, a reading that works in one system may crash another system.

To me this is the only right answer. Measurements are the net result of production and consumption. Without unwanted consumers and thriving wanted consumers the actual value is of no importance, enjoy and relax.
The only thing I woud add is also look at the general trend (and what effect a trend has on unwanted consumers) also in relation with PO4. My experience is that no matter the absolute values cyanos and certain algae will/can show up when the P:N ratio gets out of range.

 

[Belgian Anthias]

As in a reef aquarium a skimmer removes some of the organics constantly but very selective, leaving mainly polar and hydrophilic compounds, an unbalance is created between the availability of building materials and nitrogen.
In a closed life support system nitrate is just a safe way to store nitrogen to be used when needed, ready to be removed when not needed and to close the nitrogen cycle.
Why nitrate may build up in a well lit aquarium and is not used up by foto-autotrophs?
Nitrate is a regulator and an indicator.
Nitrate is very important as a nitrogen reserve to prevent nitrogen starvation. Photosynthesis and all life forms are very dependable of nitrogen availability. In the sea levels are very low but the supply is unlimited.
Nitrate is needed to complete the sulphur cycle, for removing HS produced in microbial communities when recycling the present bio-mass.
Nitrate represents nitrogen not used up due to other growth limiting factors. A decision must be made if it may be removed or used for more growth. If more photo-autotrophic growth is acceptable lowering the removal rate of a skimmer may increase the availability of usable building materials which will bring nitrate- nitrogen back into the food chain. Or food with a low nitrogen content.
If stored nitrate-nitrogen is not needed it can easily be removed as N2.

As the nitrate level can be controlled easily what is the desired level to maintain? What is the effect of nitrogen availability in the water column on microbial communities, holoboints and primary growth in combination with the availability of other nutrients and building materials?

Keeping on a level between 0.5 and 1 ppm NO3-N seems to be enough but will it be enough to go on vacation?

 

[Gregg @ ADP]

Nitrate (well, nitrogen) is definitely essential in a reef aquarium. How much is up to each system. Same with PO4.

I’m not a parameter tester, unless you count my eyeballs as testing equipment. So, it goes without saying that I’m not a number chaser. If the corals look good, then that’s how much NO3 I have. I couldn’t tell you if a tank has 5ppm NO3 or 55ppm NO3. Nor do I care all that much.

If things start moving sideways a little, I’ll see it in the algal growth, skimmate, and over-all look of the coral. 999 times out of 100, that’s due to excessive nutrients, so when I see certain indicators, I just begin remediation until it looks better.

 

[AquamanE]

Following

 

[Emerson]

Great thread, and something I've been wanting to see discussed. Thanks Rev!

I've run successful reef tanks since the late 90s, at the time mostly LPS and Soft Corals. I was out of the hobby for five years, and picked up again about the time BRS booted up their 160. Watching all the episodes, one stuck out; #48 "Solving all your reef tank's algae problems forever". Now I'm not trolling BRS. I love their videos and corporate culture to get out well researched, unbiased info in a thought out manner. But I, for one, probably took this one too far. My point being, this video advocated keeping nutrients down to a very low level to keep algae out, and boy did I. My 90 gal mixed reef tank, now two years old was cruising along supporting good growth in LPS, soft corals, and some easier SPS birdsnest, setosa, and other varieties. In fact the SPS were taking over the tank. I was very psyched to get almost unreadable NO3 (0.25 ppm Red Sea) , and 0 PO4 (Hanna ULR. My chaeto hasn't grown at all in a year. Winning, Right!?

Maybe, not so much. Four or five months ago I had a dino break out that has really knocked back my corals. Thinking maybe it's because my NO3 and PO4 levels are too low, because nothing else has worked (water changes, manual removal, etc.)

Starting this week to increase feeding (and maybe dosing NO3) in hopes of beating back the dinos and improving the coloration and growth on my SPS. Only my research into dino battle has me considering that there is a such thing as "Too Low". Here's hoping this is my way back, not chasing any number, but more than 1ppm and less than 5ppm NO3. Also pulling GFO which may have been stripping too much.

I wonder if part of this isn't a result of more accurate testing methods. Not so long ago I think test kits may have been showing low or near 0, but in reality may have been readable and closer to 5ppm NO3. Now that Red Sea reads as low as 0.25, and Hann ULR as low as 0 ppb(!) maybe we are actually that low.

Lots of posts saying that they have PO4 at 0.2-0.5ppm. Are we really meaning 0.02-0.05??? I've always thoght the number (not to chase, but as a guide) for PO4 was <0.3 ppm?