Why no nitrates!!!

[Mark75]

I have a 3 year old reef tank that refuses to produce nitrates and I am not sure why.

Salifert nitrate test shows zero,...the water is as clear as ro/di when viewed from the top or sides and I am sure this is why I am having slow SPS growth and fight bleaching if my alk gets near or above 8dkh.

It is a 50g. with 8 fish I feed very heavy and I also feed reef chili a few times a week. I do not grow macro or dose any thing to lower nutrients and have a cheap protein skimmer I run dry. I do have a small amount of matrix in my sump but mainly just so the pods have somewhere to hang out.

I have tried dosing nitrates(stump remover) and that bottomed out my nitrates, I tried feeding more and that just raised my phosphates.

I change 5 gallons of water every 2 weeks and I use kalk in my top-off water for alk/cal. Doesn't take much when nothing is growing.

test results as of last night;
cal.-410
alk.-7.7
nitrates-0
phosphates-.09

I feed rotate daily feeding 1/2 cube PE mysis/1/2 cube spiralina brine shrimp, new life spectrum pellets. I have some fat fish!

I really do not want to have to dose nitrates and phosphates. So what are my options?
More fish? Less water changes? Take the skimmer off line?

I have never seen a tank that would not produce nitrates and I have had a few down through the years!

 

[Brew12]

I would start by pulling the collection cup on your skimmer.

 

[Fishinwall]

I have the same problem...65g

 

[DenverSaltyFarm]

The best way to get nitrates up is buy a bottle of sodium nitrate and make a solution. If you stop skimming and make the water dirty, your nitrates will climb so will other toxins that might give undesirable results.

 

[uutank]

I have a 3 year old reef tank that refuses to produce nitrates and I am not sure why.

Salifert nitrate test shows zero,...the water is as clear as ro/di when viewed from the top or sides and I am sure this is why I am having slow SPS growth and fight bleaching if my alk gets near or above 8dkh.

It is a 50g. with 8 fish I feed very heavy and I also feed reef chili a few times a week. I do not grow macro or dose any thing to lower nutrients and have a cheap protein skimmer I run dry. I do have a small amount of matrix in my sump but mainly just so the pods have somewhere to hang out.

I have tried dosing nitrates(stump remover) and that bottomed out my nitrates, I tried feeding more and that just raised my phosphates.

I change 5 gallons of water every 2 weeks and I use kalk in my top-off water for alk/cal. Doesn't take much when nothing is growing.

test results as of last night;
cal.-410
alk.-7.7
nitrates-0
phosphates-.09

I feed rotate daily feeding 1/2 cube PE mysis/1/2 cube spiralina brine shrimp, new life spectrum pellets. I have some fat fish!

I really do not want to have to dose nitrates and phosphates. So what are my options?
More fish? Less water changes? Take the skimmer off line?

I have never seen a tank that would not produce nitrates and I have had a few down through the years!

I’ve the same problem for a year in my 180 gallon mixed reef. For me recently I suspected, that I was running high amount of carbon in tank. Have reduced the amount of carbon, and am hoping that it’ll make some change.
You can also try out the same.

 

[Brew12]

The best way to get nitrates up is buy a bottle of sodium nitrate and make a solution. If you stop skimming and make the water dirty, your nitrates will climb so will other toxins that might give undesirable results.

I'm not sure I would agree about skimming removing toxins. If it does, it is very inefficient at it and would have a minimal impact. What the skimmer is removing are DOC's, which some people add to their tank as coral food.

I’ve the same problem for a year in my 180 gallon mixed reef. For me recently I suspected, that I was running high amount of carbon in tank. Have reduced the amount of carbon, and am hoping that it’ll make some change.
You can also try out the same.

Carbon is very inefficient at removing NO3. If your low NO3 is causing problems, I would suggest looking for other solutions.

 

[Mark75]

I have not changed my carbon in over a year so I don’t think that is it.

I have turned my skimmer down but it never has skimmed much.

I know it doesn’t make sense but it seems my tank is not producing nitrates. Maybe it is converting nutrients into helium and they are floating out of the tank? [emoji12]

 

[Fishinwall]

Yeah I turn my skimmer off for six hours a night too.

 

[Brew12]

I have not changed my carbon in over a year so I don’t think that is it.

I have turned my skimmer down but it never has skimmed much.

I know it doesn’t make sense but it seems my tank is not producing nitrates. Maybe it is converting nutrients into helium and they are floating out of the tank? [emoji12]

Nitrates are food. If you have low nitrates in your water it means something is consuming them at the same rate you are adding them.

 

[jda]

Nitrates are not food. They are building blocks. Food is from sugars made by the zoox. Nitrates are still needed just like food, but once you have enough, then you have enough... even .1 to .5 is enough... and more cannot really do much like more food can. This of N and P needed for growth and repair whereas the day-to-day energy comes from the zoox or if a coral can catch things to eat that have carbon (unknown if SPS can do this and get anything out of it in our reefs). Light feeds the corals through zoox and N and P provide some of the building blocks necessary for organic tissue to develop.

The most likely reason that you do not have any is that in most mature tanks with good live rock and sand, the deeper places with no oxygen will have bacteria that turn No3 into N gas - they use the oxygen from the nitrate since it is not available in the water column. When this happens, you typically have a low amount of nitrate (enough of it) to drive the equilibrium forward, but not an excess. This is a good thing. This keeps the N in my tanks around .1, which is not detectable on a hobby grade test and needs IC to read it. You cannot really get to a dangerously-low nitrate level with natural methods since they rely on supply to keep the equilibrium going to support life... if you are using organic carbon or other chemicals, then you certainly can have too low of levels.

Skimming can remove metals and other inorganic toxins that bind to organics... as well as organic toxins. Most metals in some form can bind to organics and gets skimmed out... copper is one of them. Whether this is a big deal depends on each tank and what kind of salt mix is being used as well as if any metals and toxins are in the water... it might not matter to lots of people. There can also be gas exchange concerns with stopping a skimmer... which is why people recommend having more throughput (feeding more) instead of stopping a skimmer.

 

[jda]

Also, corals/clams can get nitrogen from ammonia, which should be available if you are feeding that much.

I would not sweat low nitrate. If you are having acute problems, then let us know what they are and it is probably because of something else.

 

[Brew12]

Nitrates are not food.

I guess that depends on your definition of food. If you go with Oxford: "Definition of food - any nutritious substance that people or animals eat or drink or that plants absorb in order to maintain life and growth." I would say NO3 and PO4 both apply.

You cannot really get to a dangerously-low nitrate level with natural methods since they rely on supply to keep the equilibrium going to support life... if you are using organic carbon or other chemicals, then you certainly can have too low of levels.

This I agree with. I would never use any "artificial" method to lower nitrates below 15ppm to 20ppm.

I would not sweat low nitrate. If you are having acute problems, then let us know what they are and it is probably because of something else.

Completely agree with this, also. The only time I ever worry about low nitrate is if I have cyanobacteria issues. Some strains cannot form new mats with NO3 above 3ppm. Unless you have an issue that is making you worry about nitrates, I wouldn't do anything to try and raise them.

 

[jda]

I think that it would help more people if we as a community explained the nuance and detail of building blocks vs sugars. The people who do not know better think that if they raise their N to 10 and P to .5 that their corals can use more of it, and this is not true at all. There are some nuances between lower and medium (what I consider the 2 to 20 ppm of nitrate tanks), but we cannot even get to this level until people understand that a building block cannot be used for energy. While calling N and P "food" or "nutrients" might not be technically wrong, it is also not helpful, IMO.

For example, coralline can be massively limited with nitrate over 2 to 5 as calcification is inhibited (this happens in different degrees to true coral as well)... so can cyano as pointed out above. Some inverts will reproduce in tanks with NSW levels of building blocks. In acropora, the colors are different with less or more zoox in the tissue - lower tanks have brighter colors with more contrast and some white parts on the branches of some species whereas medium level tanks will have richer, deeper colors that are more monotone and the whiter parts can get greenish... either look great, but some people prefer one over the other. There are many more, but it takes a basis of understand of what a building block is to go much further.

 

[uutank]

I read once that if you have big thick rocks, they convert nitrate to nitrogen and hence you nitrates are not present in tank. I’ll try to find and link the study if I find it.

 

[Brew12]

I think that it would help more people if we as a community explained the nuance and detail of building blocks vs sugars.

This is a very fair point. I think the push to consider NO3 a nutrient comes from the more recent trend of treating it like a poison. The reality, as you point out, is much more nuanced.

 

[Fishinwall]

Good stuff. I do run an air stone when I turn my skimmer off.

 

[Ashish Patel]

I had 0 nitrates for awhile and its more common to have this problem when you have dead rock thats not mature or producing any waste. Looking back I would much rather have decrease my photoperiod or light intensity or increase feeding, than dose nitrates which resulting in algae taking over - More so I was inpatients.

There is nothing wrong with dosing some nitrates just do it slow, when i mean slow once a week slow or at least every 3 days. Even if it registers 0 don't look for a home run the excess nutrients are being taken up and too much will result in unwanted stuff growing. After your nutrients are around 3-5PPM they will probably hold steady without dosing nitrates so this idea you have to dose nitrates is bogus, your tank is producing this stuff just adjust your skimmer or feeding in time.

High nutrients, high flow, high light all day every day.

 

[Mark75]

I have dosed nitrates in the past and did not like the results, nitrate and phosphate got really out of balance and caused problems.

The reason I am looking at my nitrate levels are my acros do not grow. After 6 months they have yet to incrust the plug and if my alk gets above 7 I start having problems bleaching, I am losing a small tri color colony right now do to me raising alk to 8.5, no stn/rtn, just a very slow bleaching over the last few months. Over the summer I neglected my tank and one day noticed my acros looked great and showing some growth, I grabbed the Hanna alk tester to see where my alk was,...5.6dkh!!! I slowly started raising it to my goal of 9dkh and I am now started to bleach and will eventually lose my only colony and I am sure the other frags/mini colonies will start showing signs.

Maybe I should keep my alk around 6dkh? Doesn't low alk cause slow growth?

 

[Scorpius]

Ever since I switched to T5's my nitrates have been in a steady decline to the point my Salifert test results are clear water. I've had lightening of several of my Acropora.

I just started dosing Brightwell nitrates last Wednesday and I see an improvement in the Acropora that were lightening up on me. It doesn't take much of this stuff to raise your nitrates to detectable which is what I'm shooting for.

 

[jda]

Nitrate is a poison at certain levels, but is is also very essential... like anything in life, right? Some, but not too much, is a good idea. How much is debatable, but somewhere between .1 and 20 seems OK... sometimes higher and sometimes lower can work too. Calcification starts to get inhibited around 2 to 5 for lots of acropora and can stop at 30-50 (or so, depending on the type)... might be 200 for some other LPS and most softies do not really care. The level to which nitrate is a poison depends on the critter... and the tank since there are few that have growth well beyond what anybody else can achieve. Again, more nuance.

For me, I don't care about a residual number on a test kit... but throughput that matters with heavy import and heavy export. This can be even more tricky since it is easier just to tell people to hit X on a test kit. My nitrates stay low - I have a 3" sand bed and I am constantly at .1 or .2 - this means VERY fast acropora and coralline growth for me, which I like for the acropora, but hate for the coralline. I just live with it since there is nothing that I could do about it anyway... even if I dosed a lot of nitrates, the bacteria in the sand would reproduce and chew them up in no time.

FWIW - clear on Salifert (through the side) can be up to 1 ppm with the error in the test kit. Only IC can test this low. If even algae is growing, then

Slow growth for acropora is related to lighting more times than not... or a new tank. If your tank is less than a year old and you are not growing coralline like crazy, then just wait longer. If your tank is stable and mature, then post up some parameters and what lights you are using. If you look at lighting as the main fuel for corals (through the zoox), then lighting should be one of the main points of focus - both quality and quantity. With the recent trend of lower quality lighting from some LED panels, just adding T5s can make all of the difference in the world for acropora growth.