Randy’s Thoughts on Nutrient Target Ranges

[Randy Holmes-Farley]

Why did you choose 0.3 instead of 0.2 or 0.5? Just curious.

I actually had it at 0.4, then moved it down. lol

There’s no strong reason for that exact number. It’s just an integration of all the info I’ve seen about what effects there may be at higher phosphate levels in reef tank, and I’ve just not really seen evidence of more problems at those levels than at lower levels.

I tried to write the recommendation as I intend to run my own tank, although in reality, if I did not detect a problem that might relate to the high phosphate, I’d probably let it run even higher. If I did see a problem that might relate, I’d lower it and see if it helps.

 

[rishma]

I actually had it at 0.4, then moved it down. lol

There’s no strong reason for that exact number. It’s just an integration of all the info I’ve seen about what effects there may be at higher phosphate levels in reef tank, and I’ve just not really seen evidence of more problems at those levels than at lower levels.

I tried to write the recommendation as I intend to run my own tank, although in reality, if I did not detect a problem that might relate to the high phosphate, I’d probably let it run even higher. If I did see a problem that might relate, I’d lower it and see if it helps.

Thanks, makes sense and seems quite reasonable.

What problems might you see that could relate to higher phosphate? Based on past exchanges, I believe you don’t tend to think of algae as more problematic at say 0.3 than 0.1.

 

[BeanAnimal]

Thanks, makes sense and seems quite reasonable.

What problems might you see that could relate to higher phosphate? Based on past exchanges, I believe you don’t tend to think of algae as more problematic at say 0.3 than 0.1.

There are likely a many differences between 0.1 and 0.3 and some may be good and others bad (in our context of growing corals). I think the takeaway is that what we would consider an overall negative effect is smaller in that range (and arguably even net positive) than say .5 or .9, or beyond.

As things mover toward (or past 1.0), those negative effects appear to be more visible and maybe surpass any positive effects. So coral may have plenty of food and want to thrive, but stunted rates of calcification, encroaching nuisance algae, changes in biofilms, etc. may cause negative impacts.

 

[Randy Holmes-Farley]

Thanks, makes sense and seems quite reasonable.

What problems might you see that could relate to higher phosphate? Based on past exchanges, I believe you don’t tend to think of algae as more problematic at say 0.3 than 0.1.

My personal plan with algae, if it becomes a problem, is to address it with fish. Worked perfectly for me last time.

I don't know what exactly might happen, but say I had a magnifica anemone that was doing fine and as phosphate drifted higher and higher it was less expanded, etc,, I might see if lowering phosphate might be the ticket to success.

 

[rhaetuluscrenatus]

Potassium is toxic, maybe the nice colour is from being poisoned, some type of response, 700 sounds excessive. I just can’t believe that corals would survive…

if depend on the form of Potassium in the water, if Potassium Chloride, yes it is toxic for most animal in high dose, but in the water, potassium is detected in many form not only KCl, so,

i remember Justin Credible kept his tank at higher 900, and some ppl said they keep their reep high:

How bad is 460 ppm potassium ?

Been dosing potassium nitrate for a few months to test effect on sps colors. Tried to maintain no3 at 5 ppm. First the corals colored up nicely, and things looked great all of last month, but last week, I started noticing gradually loss of colors. All parameters tested within range, except for...

www.reef2reef.com

 

[Randy Holmes-Farley]

if depend on the form of Potassium in the water, if Potassium Chloride, yes it is toxic for most animal in high dose, but in the water, potassium is detected in many form not only KCl, so,

i remember Justin Credible kept his tank at higher 900, and some ppl said they keep their reep high:

How bad is 460 ppm potassium ?

Been dosing potassium nitrate for a few months to test effect on sps colors. Tried to maintain no3 at 5 ppm. First the corals colored up nicely, and things looked great all of last month, but last week, I started noticing gradually loss of colors. All parameters tested within range, except for...

www.reef2reef.com

Well, that's very misleading. Potassium is not attached to anything in seawater and is always present only as K+.

It doesn't matter what form you add it in.

I personally recommend against higher than normal potassium unless it is being done as an experiment where you do not care if something has a problem. Many people report issues with elevated potassium.

@Lasse

 

[Lasse]

I have had two occasions with species specific death of fishes (with this I mean that not all species I had died but some did) The first was back in 2015 when most of my fish died during a couple of days. There was no sign of a microbial caused death. First died a batch of fishes - massive WC and it calm down. Continue with dosing additives containing potassium. A couple of months later - next death run and it also included most of my CUC.. However - my corals had never looks as good as they did during this time. I was able to send an ICP test to Triton and it shows up with around 660 mg/L K . I can´t say for sure that the problems was caused by the high K value but it got into my "aware" apartment in my brain. The second case was around 2 years ago (nov 2022). I did some changes including WC and it calm down. I send in an ICP in January and it shows around 510 mg/L. But the test was taken after a WC of around 20 % in december 2022,

I have been in the upper part with K since i started the aquarium but after the peak in January 2023 I do WC now and than with Oceamo Corrector without K in the mix. Last ICP show a rising trend and I have done a 40 L WC with 0 mg/L potassium.

As Randy point out - I cant claim that high concentrations of K is to blame in my cases. Just the suspicion is enough for me to be careful..

As I remember back around 2008 - 2010 there was a discussion about low and high K concentrations in Germany after that Korallen Zucht has start to recommend K as an additive. I do not remember the details - but maybe @Hans-Werner remember (he is younger than me )

But for me - Just the suspicion is enough for me to be careful.

Sincerely Lasse

 

[BeanAnimal]

Interesting Lasse. Thank you for the detailed thoughts.

I would also find it very interesting if you could list the other apartments in your brain, and let me know if any are for rent. May be an interesting stay.

 

[Christoph]

if depend on the form of Potassium in the water, if Potassium Chloride, yes it is toxic for most animal in high dose, but in the water, potassium is detected in many form not only KCl, so,

i remember Justin Credible kept his tank at higher 900, and some ppl said they keep their reep high:

How bad is 460 ppm potassium ?

Been dosing potassium nitrate for a few months to test effect on sps colors. Tried to maintain no3 at 5 ppm. First the corals colored up nicely, and things looked great all of last month, but last week, I started noticing gradually loss of colors. All parameters tested within range, except for...

www.reef2reef.com

Potassium is in the water as dissociated ion, it does not make any difference if it comes from KCl or other potassium salts - toxicity is the same.

I agree that significantly elevated potassium is very problematic. For examle potassium at ~1700+ mg/l can be used as a dip, killing basically everything (but coral) within a few minutes.

All the best, Christoph

 

[vahegan]

Thank you, Randy, for another great article. I think the key take is this:

The implications that aquarists need to be critically aware of are:
Nitrate level is a poor indicator of total N bioavailability.
Phosphate may also not be a good indicator of total P availability

Nitrogen in nitrate form and phosphorus in phosphate form in water are the last stage, they are converted from various other [probably organic] forms into this by bacteria, whereas their intake by corals and other organisms rather relies on these other compounds (including insoluble forms as part of food organisms). Measuring of nitrate and phosphate is therefore of little use for aquarists, it can tell us if there is too much, to the extent of suppressing coral growth, but little in terms of whether the corals are receiving sufficient nutrients.
In my tank, for example, I measure 0.03 ppm phosphate, but judging by the fact that I have to wipe the glass every other day, there is sufficient phosphorus in the water - most probably, as organic compounds.

 

[Randy Holmes-Farley]

Measuring of nitrate and phosphate is therefore of little use for aquarists, it can tell us if there is too much, to the extent of suppressing coral growth, but little in terms of whether the corals are receiving sufficient nutrients.

Thanks.

FWIW, I do not agree with the opinion quoted above. Both are useful for ensuring that there is enough N and P, even if they primarily use something else (which may or may not be true for any given reef tank).

 

[Hans-Werner]

As I remember back around 2008 - 2010 there was a discussion about low and high K concentrations in Germany after that Korallen Zucht has start to recommend K as an additive.

I was in contact with Ernst Pawlowsky at that time who was/is also a proponent of potassium additions. I asked him how much I should add and he suggested a trial where I blindly dosed potassium. I never saw an improvement. Corals got pale and grey and then they started to die. There I ended the trial.

Test that came later where only what we call "Schätzeisen", only good for raw estimates and results shifting soon.

Still I think it is easier to get and see negative effects of high potassium concentrations than it is to see problems with low potassium concentrations. Results may be different with higher phosphate/nutrient concentrations than were in the tank at that time, I don't know.

Measuring of nitrate and phosphate is therefore of little use for aquarists, it can tell us if there is too much, to the extent of suppressing coral growth, but little in terms of whether the corals are receiving sufficient nutrients.

Phosphate is a bit different. At least it is found by ICP-OES as P, even if most of the P would not be reactive phosphate found with test kits.

ICP-OES will not give you results for available N compounds. This would be a different analysis.

My position regarding nitrate is a bit different from Randy's. The color of the zooxanthellae tells you about the N status of the corals. If the corals are brown to golden brown they have some nitrogen. If they get lighter than golden brown or pale it may be a N deficiency. It is also very easy to test this: Dose ammonium according to Randy's recommendations, and you will see corals getting darker in a matter of days if it was low N availability.

Corals have so many ways to acquire N, also with their own microbiome, the bacteria in and on corals, that I generally recommend to ignore nitrate as long as corals don't get abnormally pale.

 

[Randy Holmes-Farley]

My position regarding nitrate is a bit different from Randy's. The color of the zooxanthellae tells you about the N status of the corals. If the corals are brown to golden brown they have some nitrogen. If they get lighter than golden brown or pale it may be a N deficiency. It is also very easy to test this: Dose ammonium according to Randy's recommendations, and you will see corals getting darker in a matter of days if it was low N availability.

Corals have so many ways to acquire N, also with their own microbiome, the bacteria in and on corals, that I generally recommend to ignore nitrate as long as corals don't get abnormally pale.

FWIW, I don't doubt that one may well be able to assess optimal nutrient levels in any given system by careful monitoring of the organisms present under different scenarios.

 

[CHSUB]

My position regarding nitrate is a bit different from Randy's. The color of the zooxanthellae tells you about the N status of the corals. If the corals are brown to golden brown they have some nitrogen. If they get lighter than golden brown or pale it may be a N deficiency. It is also very easy to test this: Dose ammonium according to Randy's recommendations, and you will see corals getting darker in a matter of days if it was low N availability.

Perfectly stated, imo. I will add P as having personal experience P deficiency, that appeared “fixed” with inorganic P added. I’m not ever going to add inorganic nutrients before feeding more and neither if I observe significant algae growth, including dinoflagellate.

 

[Pod_01]

The color of the zooxanthellae tells you about the N status of the corals. If the corals are brown to golden brown they have some nitrogen. If they get lighter than golden brown or pale it may be a N deficiency.

So a loaded question, what is the ideal user case for TM Amino-Organic?

Since I have a bottle handy, I just need to figure out proper application …

I hope the question fits into the larger discussion of nutrients…

 

[Randy Holmes-Farley]

So a loaded question, what is the ideal user case for TM Amino-Organic?

Since I have a bottle handy, I just need to figure out proper application …

I hope the question fits into the larger discussion of nutrients…

I understand the question is for Hans-Werner, but I'll just chime in with one comment: switching from inorganic nutrients to dissolved organic sources of N and P (e.g., amino acids for N) does not preclude the use of those same nutrients by pests such as algae and cyano.

That may not be true of organic particulates, and organic particulates may be the ticket if one's focus is feeding corals and not algae.

 

[Pod_01]

I understand the question is for Hans-Werner, but I'll just chime in with one comment: switching from inorganic nutrients to dissolved organic sources of N and P (e.g., amino acids for N) does not preclude the use of those same nutrients by pests such as algae and cyano.

That may not be true of organic particulates, and organic particulates may be the ticket if one's focus is feeding corals and not algae.

Thank you Randy, that actually helps a lot.

I didn’t realize the organic source is available to all while the inorganic source is potentially selective.

This helps me with the why I am adding certain things.

With reefing there is lot of information on what to do, the why is usually hidden by statements like “better coral growth, better colour etc…”.
From my experience when you add too many of those better things, the outcome is not better…

 

[Randy Holmes-Farley]

Thank you Randy, that actually helps a lot.

I didn’t realize the organic source is available to all while the inorganic source is potentially selective.

This helps me with the why I am adding certain things.

With reefing there is lot of information on what to do, the why is usually hidden by statements like “better coral growth, better colour etc…”.
From my experience when you add too many of those better things, the outcome is not better…

You're welcome.

Here's a study of amino acids and macroalgae:

https://www.int-res.com/articles/meps2005/294/m294p161.pdf

In laboratory experiments, we measured the uptake of small, labile DON compounds, urea and a variety of different amino acids, by the common estuarine macroalgae Ulva lactuca and Gracilaria vermiculophylla
...
Whereas both species were capable of assimilating urea and amino acids, U. lactuca consistently exhibited significantly higher uptake rates than G. vermiculophylla.
...
This study shows that macroalgae are capable of utilizing DON and that under conditions of low inorganic nitrogen availability, organic nitrogen may provide a significant portion of the total N demand.

 

[Hans-Werner]

I didn’t realize the organic source is available to all while the inorganic source is potentially selective.

@Randy Holmes-Farley , please correct me if I'm wrong but it is not what Randy said in my understanding. He said

switching from inorganic nutrients to dissolved organic sources of N and P (e.g., amino acids for N) does not preclude the use of those same nutrients by pests such as algae and cyano.

I didn't understand it the way that inorganic sources are potentially selective. I think inorganic sources are not selective.

There is another difference that may be useful: While many algae including many green algae and nuissance algae are nitrogen loving, corals are phosphate loving. Depending on which side the nutrient balance tipps, either the nitrophilic algae or the phosphate loving corals may have an advantage.

In reality it is a bit more complicated with iron and maybe other trace elements also playing a role.

 

[artieg1]

Gosh, this article is so well written! And informative! Thanks!