Nitrate mystery

[Brocksamson7]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

 

[Brocksamson7]

 

[Aqua Ultraviolet]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Zero nitrate with measurable phosphate isn’t necessarily a problem, especially if the corals are healthy, growing, and you’re not seeing nuisance algae. Your live rock, sand, bio-media, bacterial dosing, pods, and regular feeding can provide plenty of pathways for nitrogen to be consumed and converted before it accumates as measurable nitrate.
Yes, it’s possible your system is processing nitrogen efficiently enough that the water-column nitrate test stays at or near zero. I’d focus more on coral response and trends than trying to force a specific number.
If you want to raise nitrate without pushing phosphate up, reduce nutrient export slightly before adding nitrate directly. For example, you could run the fleece a little less aggressively or reduce bacterial dosing. If nitrate still stays at zero, a controlled nitrate supplement is more predictable than adding extra food, since additional feeding will usually add both nitrogen and phosphorus.

 

[Brocksamson7]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Zero nitrate with measurable phosphate isn’t necessarily a problem, especially if the corals are healthy, growing, and you’re not seeing nuisance algae. Your live rock, sand, bio-media, bacterial dosing, pods, and regular feeding can provide plenty of pathways for nitrogen to be consumed and converted before it accumates as measurable nitrate.
Yes, it’s possible your system is processing nitrogen efficiently enough that the water-column nitrate test stays at or near zero. I’d focus more on coral response and trends than trying to force a specific number.
If you want to raise nitrate without pushing phosphate up, reduce nutrient export slightly before adding nitrate directly. For example, you could run the fleece a little less aggressively or reduce bacterial dosing. If nitrate still stays at zero, a controlled nitrate supplement is more predictable than adding extra food, since additional feeding will usually add both nitrogen and phosphorus.

Thanks for the response. That’s what I figured. I guess I just want to be prepared if there comes a day I need the nitrate to fight off problems. But so far everyone is happy as a clam from what I can tell. So am I .

 

[Aqua Ultraviolet]

Thanks for the response. That’s what I figured. I guess I just want to be prepared if there comes a day I need the nitrate to fight off problems. But so far everyone is happy as a clam from what I can tell. So am I .

That makes sense. If the tank is stable and the livestock are healthy, I wouldn’t chase a specific nitrate number. Just keep monitoring it, and if things change, you can adjust gradually rather than trying to fix the number preemptively.

 

[Tanktop]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Your system consumes nitrates instantly through your live rock, sand, and bio-media before they can register on a test kit.

 

[EnterName]

Natural coral reefs have nitrate well below the detection limit of even the LR HannaChecker, so all organisms in your tank are perfectly capable of dealing with levels far below 0.25ppm NO3. As long as your corals are happy it's all good.
I don't think anecdotal evidence is worth much, but I personally ran a tank with undetectable nitrate levels for 5 years without issues and then decided to give ammonia dosing a try. I'm not sure if there is a positive effect yet.

If you decide you want to have some headroom so the tank doesn't get nitrogen limited or swarmed by dinoflagellates, I recommend dosing ammonia (https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/)

Nitrate dosing doesn't make much sense imo, as corals (and pretty much everything else) prefers ammonia. Nitrate has to be converted back to ammonia first before it can fully be assimilated and this requires enzymes build from trace elements which are more likely to be a limiting factor then nitrogen.

 

[Brocksamson7]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Your system consumes nitrates instantly through your live rock, sand, and bio-media before they can register on a test kit.

When you say consumes does that mean used or it’s holding and it’s available to my coral?
Again I’m not trying to chase the number. I’m trying to understand biologically what’s taking place and can take place.

 

[EnterName]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Your system consumes nitrates instantly through your live rock, sand, and bio-media before they can register on a test kit.

When you say consumes does that mean used or it’s holding and it’s available to my coral?
Again I’m not trying to chase the number. I’m trying to understand biologically what’s taking place and can take place.

A significant amount of ammonia is assimilated before nitrifying bacteria are oxidizing it to nitrite and nitrate so the overall nitrate levels are below the detection limit which (compared to natural coral reef nitrate levels) is really high/bad for all available hobby-grade test-kits.

Your corals have multiple ways to get nitrogen:
- Ammonia/Nitrite/Nitrate
- Urea
- Amino acids
- Heterotrophic feeding
- ...
From all of these pathways, only one is detectable with test kits at all. I wouldn't worry about a nitrogen limitation tbh . Again, ammonia dosing is the way, if you want to be on the safe side.

 

[Brocksamson7]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Your system consumes nitrates instantly through your live rock, sand, and bio-media before they can register on a test kit.

When you say consumes does that mean used or it’s holding and it’s available to my coral?
Again I’m not trying to chase the number. I’m trying to understand biologically what’s taking place and can take place.

A significant amount of ammonia is assimilated before nitrifying bacteria are oxidizing it to nitrite and nitrate so the overall nitrate levels are below the detection limit which (compared to natural coral reef nitrate levels) is really high/bad for all available hobby-grade test-kits.

Your corals have multiple ways to get nitrogen:
- Ammonia/Nitrite/Nitrate
- Urea
- Amino acids
- Heterotrophic feeding
- ...
From all of these pathways, only one is detectable with test kits at all. I wouldn't worry about a nitrogen limitation tbh . Again, ammonia dosing is the way, if you want to be on the safe side.

Killer. Thank you.
Next question. Is there any point in running a skimmer in my scenario? I don’t use one since my levels are low but should I be for other reasons?

 

[EnterName]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Your system consumes nitrates instantly through your live rock, sand, and bio-media before they can register on a test kit.

When you say consumes does that mean used or it’s holding and it’s available to my coral?
Again I’m not trying to chase the number. I’m trying to understand biologically what’s taking place and can take place.

A significant amount of ammonia is assimilated before nitrifying bacteria are oxidizing it to nitrite and nitrate so the overall nitrate levels are below the detection limit which (compared to natural coral reef nitrate levels) is really high/bad for all available hobby-grade test-kits.

Your corals have multiple ways to get nitrogen:
- Ammonia/Nitrite/Nitrate
- Urea
- Amino acids
- Heterotrophic feeding
- ...
From all of these pathways, only one is detectable with test kits at all. I wouldn't worry about a nitrogen limitation tbh . Again, ammonia dosing is the way, if you want to be on the safe side.

Killer. Thank you.
Next question. Is there any point in running a skimmer in my scenario? I don’t use one since my levels are low but should I be for other reasons?

There are two reasons I would always run a skimmer:

1. Gas exchange. It doesn't matter whether you need denitrification or not. Oxygen and CO2 are important for the entire pH balance, and sudden bacteria blooms can deplete oxygen to the point where fish might suffocate if there isn't something aerating the water. Air stones work, but a skimmer is like air stones on steroids.

2. You can't measure most of the things in your tank water. That includes organics. We don't know too much about their role in reef tanks yet, but they are often blamed for various outbreaks like cyanobacteria. Their importance becomes quite visible during carbon dosing. There is scientific evidence showing how organics fuel certain outbreaks in the ocean, but it's always difficult to tell how well that applies to reef tanks. Either way, all living beings require carbon (C), nitrogen (N), and phosphorus (P). These elements are essential building blocks of DNA, so there is no exception to this rule. Carbon is required in larger quantities than nitrogen, and nitrogen in larger quantities than phosphorus, so keeping organics (and therefore carbon) limited keeps all potential outbreaks limited. That's one possible explanation for why reef tanks can have such insanely high nutrient levels compared to natural coral reefs without constantly dealing with organisms that are known to bloom when nutrient levels are elevated. Randy's article on Liebich's law of the minimum is a good read explaining how this might work (https://www.reef2reef.com/threads/forget-redfield-liebig-is-the-man.1151779/).

 

[Randy Holmes-Farley Verified Community Expert]

There may be no reason to do anything since nitrate is not the only source of N for organisms. I discuss that in detail here, along with pictures of example tank with high and low nitrate levels:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

That said, why do you have

Tons of bio media in my sump?

I would suggest two possible things to try and see if the tank benefits:

1. Remove some or all of the biomedia. I’m not a fan of it in reef tanks since it converts ammonia that corals prefer to nitrate that they do not prefer.

2. You might experiment with dosing ammonium bicarbonate to see how the tank responds:

https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/

 

[Fish Fan]

When you say consumes does that mean used or it’s holding and it’s available to my coral?
Again I’m not trying to chase the number. I’m trying to understand biologically what’s taking place and can take place.

Just to clarify, rock and sand (unless very, very deep and dense) and biomedia do not "consume" nitrate

 

[Brocksamson7]

There may be no reason to do anything since nitrate is not the only source of N for organisms. I discuss that in detail here, along with pictures of example tank with high and low nitrate levels:

https://www.reef2reef.com/ams/randy’s-thoughts-on-nutrient-target-ranges.1087/

That said, why do you have

Tons of bio media in my sump?

I would suggest two possible things to try and see if the tank benefits:

1. Remove some or all of the biomedia. I’m not a fan of it in reef tanks since it converts ammonia that corals prefer to nitrate that they do not prefer.

2. You might experiment with dosing ammonium bicarbonate to see how the tank responds:

https://www.reef2reef.com/threads/diy-ammonia-dosing-for-low-nitrate-systems.987087/

Thanks for the response. I will read what you sent.
Tons of biomedia is probably because of the freshwater tank keeping I’ve done for years. I was also under the impression that if I had a good amount of places for bacteria in combination with pods and phyto then it would work as a system reducing the need for tons of gear, chemicals, and other mechanical ways of filtration. Not to be frugal but to not get lost in the balancing act of a bunch of stuff that’s “overkill”.
When you say you’re not a fan are you saying you prefer to run no biomedia or just a light amount?

 

[Randy Holmes-Farley Verified Community Expert]

I have a hypothesis that biomedia is a net negative in most reef tanks since corals prefer to take up ammonia, and the bacteria are just stealing it from them, converting it into something they have to spend energy to use:nitrate.

I have no biomedia.

 

[Fish Fan]

When you say you’re not a fan are you saying you prefer to run no biomedia or just a light amount?

Keep in mind that your rocks, sand and even many other surfaces will all grow nitrifying bacteria, so the rock and sand can be thought of as your primary biofilter. And typically that's more than enough.

 

[Brocksamson7]

Excellent. Thank you everyone for your help. Makes sense.

 

[Dan_P]

I have a hypothesis that biomedia is a net negative in most reef tanks since corals prefer to take up ammonia, and the bacteria are just stealing it from them, converting it into something they have to spend energy to use:nitrate.

I have no biomedia.

I am having trouble with your hypothesis. It implies that more surface area means more nitrifying bacteria to feed or steal ammonia. Only a certain bacteria population size (approximately) can exist for a given amount of food (energy) in the aquarium. Surface area does not seem to drive bacteria population size. Also, very little nitrifying microorganism DNA is found in aquaria, likely because of its tiny population size. And be ause of carbon limitation, it isn’t likely heterotrophic bacteria are stealing ammonia.

 

[Fish Fan]

Also, very little nitrifying microorganism DNA is found in aquaria, likely because of its tiny population size.

I thought it was still the subject of some debate exactly what organisms are nitrifiers in home aquaria, so can you make this statement with confidence?

Thanks for your help!

 

[Randy Holmes-Farley Verified Community Expert]

I am having trouble with your hypothesis. It implies that more surface area means more nitrifying bacteria to feed or steal ammonia. Only a certain bacteria population size (approximately) can exist for a given amount of food (energy) in the aquarium. Surface area does not seem to drive bacteria population size. Also, very little nitrifying microorganism DNA is found in aquaria, likely because of its tiny population size. And be ause of carbon limitation, it isn’t likely heterotrophic bacteria are stealing ammonia.

It seems logical to me, and while I cannot know the magnitude of the effect, I’m relatively confident it is real. Taken to an absurd extreme, the alternative view is that a vanishingly small amount of surface area will have just as much nitrifying capacity as a large amount of surface area.

There are many different organisms that will take up ammonia. They occupy different spaces in the aquarium. If one makes a large amount of real estate that is only available to microorganisms, microorganisms will be able to take up more and other organisms less, just like having 500 corals might take up more than a single coral of the same size.