SPS: How much is too much Nitrate?

[ScottB]

In my 300G frag system my nitrates have been boringly static around 10. During a little bout of dinos I had to dose but that was a year ago. Since then, I have more and larger fish and modest refugium hours because it always stayed around 10. I didn't test much after dinos; just look at corals.

A couple months ago some tenuis started STN from the base. Over time it kept happening -- fairly species specific. Come to realize my NO3 tests are a bit old.

Between new NYOS and Red Sea I have +40 nitrates now.

Who believes this could be an issue? I have seen people laugh off high PO4 (about .14 and generally steady in low teens for me) but can't recall people freaking about a nitrate threshold. I have several inch-thick tangs that keep the lawn mowed OK. But when do acros reject high nitrate levels?

I have now turned up the 'fuge lights for 20 hours and started a minimal carbon dose (ascetic 10 ml) to pull nitrates back again. Also WC schedule is moving to weekly vs 2 weeks.

When do you see nitrates becoming a problem for tenuis or the larger SPS community?

 

[Gablami]

Following...

 

[BranchingHammer]

Just be careful with carbon dosing. Your sps have been used to that level for so long and have been fine with it, so you shouldn't decrease it quickly at all. I would suggest more refugium hours, and watch nitrate, and if it isn't budging, then bring in the carbon dosing slowly. But definitely, everything extremely slow... just my $0.02.

 

[ScottB]

@BranchingHammer roger that. Gotta remind myself not to pull too many levers at the same time. I will diligently test until I get to a happy level.

We've all seen beautiful systems with high PO4, but I am failing to recall ones with nitrates like where I am at now with 40+ to my eyes. My son thinks they are even higher.

@Chaswood79 I know you run heavy in/out. What is your MAX nitrate level with/without trouble?

 

[Charlie’s Frags]

@BranchingHammer roger that. Gotta remind myself not to pull too many levers at the same time. I will diligently test until I get to a happy level.

We've all seen beautiful systems with high PO4, but I am failing to recall ones with nitrates like where I am at now with 40+ to my eyes. My son thinks they are even higher.

@Chaswood79 I know you run heavy in/out. What is your MAX nitrate level with/without trouble?

I haven’t ever had a problems from higher than recommended no3 or po4. I only had issues my first year getting back into sps chasing recommended no3/po4 with carbon dosing and gfo. If my no3/po4 gets above 25/0.25 I’ll slowly bring it down with extra fuge hours and LC.

 

[ScottB]

Update:
Can't be absolutely certain why my tenuis troubles have abated, but they have. Nitrates now back down to 25+- so about half of where they were at peak. Still just 10ml vinegar and 20+ hours on refugium light. Phosphates aren't moving: still .13 which I am fine with.

Everything else is unchanged and the necrosis has stopped. Might even be seeing a little more PE too.

While it MAY be that the carbon dosing is enhancing the bacterial health in the tank, I really "feel" like my my high residual NO3 was the primary problem.

 

[jda]

It depends on what you are keeping. Some acropora won't care at all even at double that amount. Some can STN and die with half of that amount, or even lower. Not all acropora will thrive in higher N tanks, but not everybody should care since there are plenty that do quite well. It is much too simple to say that since some acropora do fine in high N tanks that all will, which is where the board tends to go with "my nitrate is X and my acros are fine" with no nuance or details about what they cannot keep (if they even know what they cannot keep).

To be clear, most higher nitrate tanks usually have PLENTY of available nitrogen, which is doing the work, not the residual nitrate. It is OK to have much lower residual levels, but you cannot also have low availability by using chemicals, media or stopping feeding. You still need heavy import in low residual tanks. Availability is the prize.

As long as you didn't stop feeding as much, then I can believe that the lower residuals did you well. Acropora can catch bacteria and assimilate them through their slime layer, when healthy, which helps them get available resources - this becomes a math problem since the tank turnover and skimmer is much more effective than the surface area of smaller corals (larger corals have an advantage). You really need to stop/slow the organic carbon dosing when you get lower in the N range since you can go too far... or really up the feedings. Zeo doses organic carbon, but also adds all kinds of stuff to the tank to compensate and keep availability high.

As most of you know, my N is around .1, but my tank keeps them there and I really have no choice in the matter. This is no issue, but I also do nothing to strip the water of available nitrogen by dosing chemicals, media or organic carbon. I would probably be OK up to 3 or 5, but after that, some of my smoothies would stop growing and then STN a bit. Most growth slows for me at 10-15, but again, that is not a super bad thing. There are some corals that look fine and grow OK up to about 30-40, but suffer beyond. As thales can show you, there are some acropora that do OK at twice that level, or more, but few that I want to keep. Any of them do well at .1 with lots of available nitrogen... all of them.

Availability, not numbers on a backend test kit. My guess is that if you get that N down to 5 or 10 (SLOWLY) that you will see even better results as long as you keep the availability good. Let me know what number you see coralline take off like crazy and become a true nuisance... it will happen if you keep it up.

 

[ScottB]

It depends on what you are keeping. Some acropora won't care at all even at double that amount. Some can STN and die with half of that amount, or even lower. Not all acropora will thrive in higher N tanks, but not everybody should care since there are plenty that do quite well. It is much too simple to say that since some acropora do fine in high N tanks that all will, which is where the board tends to go with "my nitrate is X and my acros are fine" with no nuance or details about what they cannot keep (if they even know what they cannot keep).

To be clear, most higher nitrate tanks usually have PLENTY of available nitrogen, which is doing the work, not the residual nitrate. It is OK to have much lower residual levels, but you cannot also have low availability by using chemicals, media or stopping feeding. You still need heavy import in low residual tanks. Availability is the prize.

As long as you didn't stop feeding as much, then I can believe that the lower residuals did you well. Acropora can catch bacteria and assimilate them through their slime layer, when healthy, which helps them get available resources - this becomes a math problem since the tank turnover and skimmer is much more effective than the surface area of smaller corals (larger corals have an advantage). You really need to stop/slow the organic carbon dosing when you get lower in the N range since you can go too far... or really up the feedings. Zeo doses organic carbon, but also adds all kinds of stuff to the tank to compensate and keep availability high.

As most of you know, my N is around .1, but my tank keeps them there and I really have no choice in the matter. This is no issue, but I also do nothing to strip the water of available nitrogen by dosing chemicals, media or organic carbon. I would probably be OK up to 3 or 5, but after that, some of my smoothies would stop growing and then STN a bit. Most growth slows for me at 10-15, but again, that is not a super bad thing. There are some corals that look fine and grow OK up to about 30-40, but suffer beyond. As thales can show you, there are some acropora that do OK at twice that level, or more, but few that I want to keep. Any of them do well at .1 with lots of available nitrogen... all of them.

Availability, not numbers on a backend test kit. My guess is that if you get that N down to 5 or 10 (SLOWLY) that you will see even better results as long as you keep the availability good. Let me know what number you see coralline take off like crazy and become a true nuisance... it will happen if you keep it up.

Your mention of species specific reaction to residual nitrate rings very true with this experience. I've had that colony for many years, but this was peak bioload for sure (in the frag system). The residual just got away from me. For years the display ran just barely >0 for both and that colony thrived. Others, less so and more pale. As I let it go more dirty (with more fish) everyone seemed to do better to the point I had to chop up everything.

New lessons all the time.

 

[Reefahholic]

I have good luck with P at 0.05 to 0.15 but I’ll let it get as high as 0.2 before I start to feed less or do some smaller water changes. No chemicals for me unless it’s really needed and even then I try to avoid it.

I like my N at least 2-3 minimal and up to 10. I try to keep it under 20 at the highest end. My tank seems to do the best at 3-10. I’m sure it will be ok over 10, but 40 is too much in my opinion. I think it slows growth.

There’s so many other things that contribute to these numbers so it’s really impossible to say that a certain number or even a range is good for every tank.

It depends on the lighting, how much you feed, how deep the tank is, nutrition going into the tank, water changes, flow, etc.

 

[ScottB]

It depends on what you are keeping. Some acropora won't care at all even at double that amount. Some can STN and die with half of that amount, or even lower. Not all acropora will thrive in higher N tanks, but not everybody should care since there are plenty that do quite well. It is much too simple to say that since some acropora do fine in high N tanks that all will, which is where the board tends to go with "my nitrate is X and my acros are fine" with no nuance or details about what they cannot keep (if they even know what they cannot keep).

To be clear, most higher nitrate tanks usually have PLENTY of available nitrogen, which is doing the work, not the residual nitrate. It is OK to have much lower residual levels, but you cannot also have low availability by using chemicals, media or stopping feeding. You still need heavy import in low residual tanks. Availability is the prize.

As long as you didn't stop feeding as much, then I can believe that the lower residuals did you well. Acropora can catch bacteria and assimilate them through their slime layer, when healthy, which helps them get available resources - this becomes a math problem since the tank turnover and skimmer is much more effective than the surface area of smaller corals (larger corals have an advantage). You really need to stop/slow the organic carbon dosing when you get lower in the N range since you can go too far... or really up the feedings. Zeo doses organic carbon, but also adds all kinds of stuff to the tank to compensate and keep availability high.

As most of you know, my N is around .1, but my tank keeps them there and I really have no choice in the matter. This is no issue, but I also do nothing to strip the water of available nitrogen by dosing chemicals, media or organic carbon. I would probably be OK up to 3 or 5, but after that, some of my smoothies would stop growing and then STN a bit. Most growth slows for me at 10-15, but again, that is not a super bad thing. There are some corals that look fine and grow OK up to about 30-40, but suffer beyond. As thales can show you, there are some acropora that do OK at twice that level, or more, but few that I want to keep. Any of them do well at .1 with lots of available nitrogen... all of them.

Availability, not numbers on a backend test kit. My guess is that if you get that N down to 5 or 10 (SLOWLY) that you will see even better results as long as you keep the availability good. Let me know what number you see coralline take off like crazy and become a true nuisance... it will happen if you keep it up.

Funny you mention the coralline. It is something that over time I took for granted; it just covered everything. Now with higher nitrates, there are several other algae contenders for the same space. It just happens so slow that I missed that transition. It used to be that when I soaked a frag rack in vinegar, the bucket would go pink with dissolved coralline. Now, it just goes kinda gunky in color.

Another 50G WC coming up!

 

[ScottB]

I have good luck with P at 0.05 to 0.15 but I’ll let it get as high as 0.2 before I start to feed less or do some smaller water changes. No chemicals for me unless it’s really needed and even then I try to avoid it.

I like my N at least 2-3 minimal and up to 10. I try to keep it under 20 at the highest end. My tank seems to do the best at 3-10. I’m sure it will be ok over 10, but 40 is too much in my opinion. I think it slows growth.

There’s so many other things that contribute to these numbers so it’s really impossible to say that a certain number or even a range is good for every tank.

It depends on the lighting, how much you feed, how deep the tank is, nutrition going into the tank, water changes, flow, etc.

Your numbers do sound conventional. I will return to those slowly. My initial increase in nutrient was intentional to fight off ostreopsis dinoflagellates about a year ago. Then when my test kit started to go bad (always reading 10), nitrate really got away from me.

I feed a lot of fish food (frozen & nori) to a lot of big fish. My skimmer is undersized, my refugium was running short cycle before but now around 20 hours. I run flow as high as I can without it blowing plugs off the rack. Light is T5/LED; 8 hours full and four of ramp time. CaRx and IORC for WCs (knocked down to 8.5 dKH).

I am actually rather relieved now that I understand my nitrates were out. I was pulling out what hair remains trying to figure out why these frags were going white from the base.

 

[ScottB]

I haven’t ever had a problems from higher than recommended no3 or po4. I only had issues my first year getting back into sps chasing recommended no3/po4 with carbon dosing and gfo. If my no3/po4 gets above 25/0.25 I’ll slowly bring it down with extra fuge hours and LC.

Just curious. Since the time you first began using LC, have you ever had aefw?

I ask this after having read the Coral Magazine article about LC killing aefw.

 

[Charlie’s Frags]

Just curious. Since the time you first began using LC, have you ever had aefw?

I ask this after having read the Coral Magazine article about LC killing aefw.

I’ve never even seen an aefw in person

 

[ScottB]

I’ve never even seen an aefw in person

Keep it that way. Pain in the rear to solve for. I obviously missed some eggs on the way in, but no clue on the source.