My Collected Thoughts on N and P Dosing

[DarkSky]

The two coral farms I've visited were both dosing nitrates and phosphates, as well as running their alk in the 10s. Profit for them is faster coral growth, so they wouldn't be doing it if it didn't directly benefit their bottom line.

The anecdotal evidence and research points to a surplus being beneficial. SPS may prefer to get its nitrogen from ammonia, but it is more than capable at taking it in from NO3. Plus, I feel much safer dosing NO3 to my tank versus ammonia and harming my fish.

Sorry @jda, I'm going to have to disagree with your hypothesis on this.

 

[FlyPenFly]

Dosing ammonia though is a very interesting idea, I imagine though it gets eaten by bacteria and algae faster than the coral can get to it but that’s just a theory.

Fish definitely directly produce ammonia though so maybe heavily stocking a sps tank has some merit.

And I’m not sure if it might benefit some types of sps and might hurt others like lps. Worth investigation though.

 

[Big E]

The two coral farms I've visited were both dosing nitrates and phosphates, as well as running their alk in the 10s. Profit for them is faster coral growth, so they wouldn't be doing it if it didn't directly benefit their bottom line.

The anecdotal evidence and research points to a surplus being beneficial. SPS may prefer to get its nitrogen from ammonia, but it is more than capable at taking it in from NO3. Plus, I feel much safer dosing NO3 to my tank versus ammonia and harming my fish.

Sorry @jda, I'm going to have to disagree with your hypothesis on this.

Can you be more specific on your observations of these coral farms? How many fish were in these grow out systems? With very few there isn't any ammonium for the corals let alone NO3 or P04.

My anedotal evidence points to corals benefiting more from the front end nutrient uptake vs nitrate and phosphate dosing.

Their systems are runways of heavy loads of corals, not quite the same as a display tank.

The alk observation is another separate thought process I'm not sure I buy into. Higher alk readings is just surplus sitting there.........I'm not sure it's a benefit., but that's probably for another thread.

 

[SeaDweller]

I am not sure I am following this. I am not arguing the point just trying to understand the reasoning. Some points have been brought up which merit consideration

Why do you think burnt tips are from accelerated growth (I presume you mean calcification and in particular skeletal growth). Why do you presume calcification is accelerated and why do you presume tissue cannot keep up. Perhaps something else is taking place that is not increasing calcification but simply injuring the tissue.

Lastly, this is the part I am most confused about. You state: “You have to keep alk down to limit calcification...in the 6’s.” And then your next sentence seems to contradict this, “Ocean got this right...low alk and low N and P give the fastest growth”. Maybe I just am missing the point but it seems in one sentence low alk slows calcification and in the next sentence low alk and low N and P increases calcification.

The next responder, Flypenfly, states that “....high levels (alk, ca, mg and trace), high pH, and moderate amounts of nutrients grow SPS quicker and with better coloration.”

So which is it higher alk or lower alk, low nutrients or moderate amount of nutrients.

Watchguy, you’re definitely a seasoned vet in this hobby. Ive read some of your articles and read thru your thread (I’m in So Cal, so the new talks of shutting of electricity if there are fires scare me), what’s your stance with this issue? Where did you see the most success regarding nutrient levels?

 

[Graffiti Spot]

I am not sure I am following this. I am not arguing the point just trying to understand the reasoning. Some points have been brought up which merit consideration

Why do you think burnt tips are from accelerated growth (I presume you mean calcification and in particular skeletal growth). Why do you presume calcification is accelerated and why do you presume tissue cannot keep up. Perhaps something else is taking place that is not increasing calcification but simply injuring the tissue.

Lastly, this is the part I am most confused about. You state: “You have to keep alk down to limit calcification...in the 6’s.” And then your next sentence seems to contradict this, “Ocean got this right...low alk and low N and P give the fastest growth”. Maybe I just am missing the point but it seems in one sentence low alk slows calcification and in the next sentence low alk and low N and P increases calcification.

The next responder, Flypenfly, states that “....high levels (alk, ca, mg and trace), high pH, and moderate amounts of nutrients grow SPS quicker and with better coloration.”

So which is it higher alk or lower alk, low nutrients or moderate amount of nutrients.

Pretty sure he meant that low alk with low nutrients is needed to avoid burnt tips in general. I don’t think that all burnt tips are the same though. A fluctuation can cause the tips tissue to burn off but burnt tips can also happen when growth happens too fast, but I believe this looks different than what most of us would consider to be burnt tips. Sometimes this can just be very translucent looking new growth from the coral growing so quickly. I would like to hear some of seasoned reefers thoughts on this too.
I am not sure that flypenfly’s thoughts on high alk and nutrients are completely true for everyone, some coral farms are running their tanks this way because it’s what is easiest and safest for them. Although certain acropora do seem to grow faster in this situation, one example is the Italians and the blue coral method. They were growing certain staghorns and lps at crazy rates, and the method uses high alk, but not all their corals grew at these enhanced rates.
The blu coral method is the only example I can think of to argue that some species of acropora can grow faster while being fed. But even then, it’s actually more of a whole system feed that’s happening and benefiting the coral. I think it’s hard to say that the food is directly benefiting these corals growth even in this situation. I have not seen anyone outside of those documented threads have the success that these reefers had although a lot of people have tried. That is with massive large coral colonies growing extremely fast.
The whole coloration part of this topic is subjective. But I do like this thread so keep it going.

 

[FlyPenFly]

Some good reading on this:

https://www.advancedaquarist.com/2015/2/aafeature

SPS corals can ingest and assimilate bacteria, green algae, dinoflagellates, ciliates, and larger zooplankton.
Organic phosphorus (bound in bacteria tissue) is the preferred phosphate source (as opposed to dissolved reactive phosphate.)
Some algae often grown in aquaria (Halimeda and Caulerpa) release carbohydrates (sugar) that be absorbed by corals. Glucose is the preferred sugar of some Fungia specimens.
Ammonium is preferentially absorbed by corals. Nitrate is also absorbed.
Fish poop is a potential source of nitrogen and phosphorus.
Urea (from fishes, and a source of nitrogen) can be absorbed.
Even well-maintained aquaria (protein skimmers, filter socks) can contain suspended organic matter.
Some corals are host to nitrogen-fixing bacteria. These are a source of nutriment when they die (or are consumed.)
Amino acids (either combined or free) can be a nitrogen source.

Definitely more investigating to do but I'm pretty convinced for most acros, elevated levels can be very beneficial for growth and color. Perhaps not all. Here's the BRSTV look at this:

 

[Graffiti Spot]

I didn’t watch the whole video but I don’t see the lower alk corals in that video looking healthy. I think we could poke some holes in their study if we really wanted to. The way I look at it is the same as big e, higher levels are just a surplus of it. There is way to much involved in this topic to have this study carry any weight. Higher levels means dosing more, and they are selling what your dosing. I have seen many tanks with higher levels and none of them made me think anything was growing faster than average.

 

[FlyPenFly]

They’re pretty fair about things. Those guys are hobbyists like you and me. They actually kind of discourage the use of GFO even though that’s one of their main profit centers. They also talk a lot about the negatives of carbon even though they sell some of the best.

Also once your levels are elevated, it doesn’t take more material to keep them elevated unless you’re seeing more growth.

IMO, they take a long term view. The more successful hobbyists there are, the more customers they will have who don’t quit and give up. They are probably the biggest vendor now for hobby reefing so it’s in their long term interest to promote the growth of the market.

 

[jda]

Hey Watchguy - it is science that calcification is faster with lower amounts of N and P - growth does not stop, but it slows down as N and P rises. In the case of burnt tips, the acro calcifies faster than the tissue can grow and it pushes right out the end of the soft tissue. You have to keep alk down to limit the calcification. This is how the ocean does it... and corals evolved. This is not to be confused with LED lighting burnt tips, which is different. It was once normal to keep higher alk levels around 9-12. Once organic carbon dosing got hot, then people could get their N and P too low and this is when burnt tips got common. It has kinda subsided since there is no real issue with keeping alk near 6 or 7, so why risk it - there are even salt mixes now that are made for this (or you can use Muratic Acid like lots of us do). The burnt tips were a side journey in the evolution of some reef keeping styles about a decade ago.

There are links to all kinds of real science, peer reviewed stuff that Dr. RHF wrote to write his nitrate and phosphate articles. If you ever had NSW levels N and P, then you would see the massive amount of coralline growth and new tip growth everywhere with acropora. Most of these articles were still available the last time that I looked.

I don't care if anybody agrees with me or not. If you think that you can grow corals faster in an actual tank with an actual hobbyist, then do it. You probably won't be able to, but if you can, you can probably speak at MACNA about it. If nobody gets anything else out of this, go back in time to your basic biology class and remember that building blocks are not like food - more does not mean that an organsim can do anything with them... at best they ignore or expel them... and too many are poison to all living creatures (in different amounts for each).

 

[jda]

So which is it higher alk or lower alk, low nutrients or moderate amount of nutrients.

The only thing that I can offer here is to look at people's growth. I post photos of mine. which you have likely seen. I would put it up against anybody's on the board. I would also put Ed's (sorry Ed) up against anybody too. We share pretty similar experiences that we gathered on our own and did not just read, or watch a video, to obtain. Does anybody on this thread with different ideas care to demonstrate their acumen with their approach?

 

[Charlie’s Frags]

I’ve seen the fastest growth in the last 6 weeks with my alk 7.8-8.3 and 0.10-0.20 po4. Could be a coincidence because I also increased my peak photo period from 6 to 9 hours. This thread encouraged me to feed more, which I did, and my po4 went up. But I haven’t worried about it because my acros are growing faster than ever.
https://www.reef2reef.com/threads/some-crazy-6-week-growth.598383/

 

[reef_ranch]

Hey Watchguy - it is science that calcification is faster with lower amounts of N and P - growth does not stop, but it slows down as N and P rises. In the case of burnt tips, the acro calcifies faster than the tissue can grow and it pushes right out the end of the soft tissue. You have to keep alk down to limit the calcification. This is how the ocean does it... and corals evolved. This is not to be confused with LED lighting burnt tips, which is different. It was once normal to keep higher alk levels around 9-12. Once organic carbon dosing got hot, then people could get their N and P too low and this is when burnt tips got common. It has kinda subsided since there is no real issue with keeping alk near 6 or 7, so why risk it - there are even salt mixes now that are made for this (or you can use Muratic Acid like lots of us do). The burnt tips were a side journey in the evolution of some reef keeping styles about a decade ago.

There are links to all kinds of real science, peer reviewed stuff that Dr. RHF wrote to write his nitrate and phosphate articles. If you ever had NSW levels N and P, then you would see the massive amount of coralline growth and new tip growth everywhere with acropora. Most of these articles were still available the last time that I looked.

I don't care if anybody agrees with me or not. If you think that you can grow corals faster in an actual tank with an actual hobbyist, then do it. You probably won't be able to, but if you can, you can probably speak at MACNA about it. If nobody gets anything else out of this, go back in time to your basic biology class and remember that building blocks are not like food - more does not mean that an organsim can do anything with them... at best they ignore or expel them... and too many are poison to all living creatures (in different amounts for each).

I don’t believe this description of burnt tips is at all accurate. The calcified coral skeleton does not grow on its own, popping out from the tissue. The coral polyps lay down calcium underneath it, thereby enlarging the colony. Burnt tips, be it from LED burning or high alk are the same result of two separate causes - the coral tissue that was covering the skeleton dies or recedes, exposing the skeleton. I’ve experienced burnt tip from both of these causes and, anecdotally, have found it occurs when my alk is out of balance with the nutrients (higher than 9 with NO3 below 5 and PO4 below .03). Fast growing corals have fewer zooxanthellae in the new growth and that’s why the tips are pale. But they are covered in tissue, unlike burnt tips.

In my experience, I get better growth, but not necessarily better color, when the nutrients are around 10/.1 , alk is around 8.5 and pH is above 8. I also find there is a better “margin for error” than when I keep nutrients super low. But, I find the brightest colors are pulled when the nutrients are pretty low and the alk is mid 7’s. Since I prefer colors over growth, that’s where I try to keep my tank. I’ve recently increased my fish loan and found that my PO4 crept up to .14. I increased my alk to 8.5 and am slowly dropping the PO4. Growth has increased and the coral tissue has darkened.

 

[SeaDweller]

I don’t believe this description of burnt tips is at all accurate. The calcified coral skeleton does not grow on its own, popping out from the tissue. The coral polyps lay down calcium underneath it, thereby enlarging the colony. Burnt tips, be it from LED burning or high alk are the same result of two separate causes - the coral tissue that was covering the skeleton dies or recedes, exposing the skeleton. I’ve experienced burnt tip from both of these causes and, anecdotally, have found it occurs when my alk is out of balance with the nutrients (higher than 9 with NO3 below 5 and PO4 below .03). Fast growing corals have fewer zooxanthellae in the new growth and that’s why the tips are pale. But they are covered in tissue, unlike burnt tips.

In my experience, I get better growth, but not necessarily better color, when the nutrients are around 10/.1 , alk is around 8.5 and pH is above 8. I also find there is a better “margin for error” than when I keep nutrients super low. But, I find the brightest colors are pulled when the nutrients are pretty low and the alk is mid 7’s. Since I prefer colors over growth, that’s where I try to keep my tank. I’ve recently increased my fish loan and found that my PO4 crept up to .14. I increased my alk to 8.5 and am slowly dropping the PO4. Growth has increased and the coral tissue has darkened.

So what’ll you do when your PO4 drops back down to say 0.10 or slightly below, will you drop your alk back down into the sub 8.0 range? Or will you maintain 8.5 dkh and keep the PO4 at 0.10 or below? IF (emphasized “if”) your plan is to drop PO4 to 0.10 or below, why not just keep alk at Sub 8.0 and just bring PO4 down? Just want to pick your brain, that’s all [emoji106]

 

[Charlie’s Frags]

I didn’t have burnt tips when my alk was above 8 and my po4 was sub 0.03. I firmly believe burnt tips happen from artificially driving po4 down. I don’t believe it’s the number but methodology behind that number. I had burnt tips when my po4 was high and my alk was low but I was using gfo and bio pellets.

 

[jda]

IME, you have to get down to 0 ppb to have burnt tips from the calcification outdoing the tissue growth. The only time that I have ever really seen it was with aggressive organic carbon dosing.

 

[watchguy123]

I reread the original post in the thread and there is a lot of information and questions to think about.

I don’t necessarily agree that nitrate dosing is not doing anything. I think that might be presumptuous. I also don’t think we have any reasonable idea about amounts of ammonia being produced and if adequate ammonia is available or not.

I obviously need a primer in biological processes because I’ve forgotten most of my biochem and physiology. But I think our fish and other organisms consume the food we feed them and then produce ammonia among other byproducts. The ammonia and ammonium are converted by algae and bacteria to nitrates and nitrites (nitrogen cycle). And our “preferred” critters , coral—sps and lps, then use the nitrogen as part of their building blocks along with carbon and phosphate.

So there is no ammonia additive specifically that I have heard of. But if we add more fish ( and other critters such as shrimp and crabs and snails) we can get more ammonia by adding food for them to consume, digest and release ammonia. Unconsumed food will lead to more ammonia production as well. However, too much ammonia and it becomes toxic. Too much food and there is an over abundance of both nitrates and phosphates.

I may be standing on shaky footing, but I think nitrate dosing adds available nitrogen.

Additionally, I think nitrate dosing with lower nitrate levels also may push phosphates lower (sometimes a very good result). When additional nitrate is sought by purposeful feeding additions, I believe that elevates both nitrates and phosphates but the latter disproportionately. However, if both phosphates and nitrates are low, feeding more is likely the best choice. I think consensus ( now I may be presumptuous) is that if either nitrates or phosphates bottom out, then something bad is taking place eg, algae bloom, inadequate feeding, starving tank, etc or something bad is about to happen eg. Cyano bloom, Dino bloom, etc

I think the ocean is the best example of low alkalinity and low nitrates and phosphates. But I’m not sure it translates perfectly to our tanks because, well, are tanks are not the ocean.

I think tanks do well with 7ish dKh and nitrates 1-5 ppm and phosphates .03 ppm. I aim for around 7.5 dKh and nitrates 1-10 ppm and phosphates less than .1 but above .03 ppm. But reefers have been all over the map with their levels and done well. Tanks do great in a large range of alkalinity as well as nitrates and phosphates. General rules, for what they are worth, low alk (6.5-8dKh) with nitrates 1-10 ppm and phosphates from .1 - .03 ppm seems to be a pretty good zone as well as higher alk (9-13 dKh) with nitrates 5-20 and phosphates less than .15 ppm. Those ranges are not from articles but what hobbyists have shared. I’m not well versed on the scientific articles available, I guess because I haven’t encountered that many articles that were that relevant except of course for RHF about reef chemistry articles but those are really summaries of current knowledge.


I like reading articles as well as reading about reefer experiences and I like videos. Even scientific articles just like reefer experiences all require a bit of healthy skepticism and consideration.

I don’t think the science says that ocean like parameters in a reef tank provides the best growth rate. I don’t know how any of us really can put a number or descriptor on growth rates in our tanks. Some corals grow like weeds, some
sit around forever before they take off. Most of us have seen the change in growth rate that takes place as frags grow from one inch to mini colonies to baseball size and then softball size. It seems ultimately they grow almost faster than can be trimmed. On the other hand, I seem to hit a blip every three to four years with one thing or another in my tank. So I may not be the best resource for success but at least I persist

I just want to add a caveat to all this. It’s hard to understand tone and intent in these exchanges. I love this sort of dialogue and exchange of thought. Sometimes some comment may come across as harsh. That is not my intent. I wish I was better educated about reefing. Additionally, individuals like myself present an idea or thought as factual when it really isn’t. I’m guilty of this as probably others are as well. But eventually, hopefully we get to truths and better understanding.

 

[jda]

Yes, ammonia and ammonium are necessary in small amounts just to keep the equilibrium going forward and consuming organsims supplied with nitrogen. Excess is a poison in varying amounts to any living creature. For sure. Why is this any different for N and P? Needed in small quantities with excess being a poison at varying levels. For sure.

Don't worry about harsh comments. If people cannot put their big-boy pants on and wipe away their pouty lip, then they will never learn anything or get better in life. Post away...

The only thing that I will say about science is that all true science assumes that the current standard is correct until unequivocally proven otherwise (or close to it). In this case the current standard is nature. No true scientist would argue that nature is not right unless they could prove beyond a peer-reviewed doubt. Anything else is pseudoscience... this can be useful, but it is different. The most blatant example of this that I can think of is the LED light companies asking for proof that UV light is useful when they should have been proving that it isn't - this has come back to be a known falsity, but this could have been avoided if a solid scientific approach was used from the get-go.

This is an OK read on ammonia and ammonium. There is a lot of hobbyist dribble on this thread based on pseudoscience and false equivalency (like detritus being full of ammonia and macroalgae being a huge consumer - premise is OK, but wrong type of organism), but there is some good stuff too if you can ignore some of the rest. If nothing else, read the posts from Lasse and the ones that he answers - he is pretty spot-on. nh3 and nh4 is preferred over no3 since there is less energy consumed to convert it... and single cell organisms, like the dinos in the coral, are adept at doing this. nh3 and nh4 are constantly being made in the tank and available in small quantities for uptake.
https://www.reef2reef.com/threads/1...mmonia-is-causing-your-algae-problems.558661/

If you get your tank into the range of the parameters in this article, everybody will do better, IMO:
http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Here is a good quote, since people seem to think that he is smart and I am dumb. This quote is true and if you think that you have good growth at 10ppm of N and .10 ppm of P, then you would be astonished about what would happen if you lower it. This is one thing that you don't know unless you know.

If allowed to rise above natural levels, phosphate can cause two undesirable results. One is inhibition of calcification. That is, it can reduce the rate at which corals and coralline algae can build calcium carbonate skeletons, potentially stunting their growth.

 

[FlyPenFly]

The question I have of ammonium as a nutrient source is if it can even get to the coral or if it's so quickly absorbed by nitrifying bacteria that it never makes it. We know that the nitrate to nitrogen gas processing bacteria need special conditions that only exist in certain oxygen free areas of the tank (DSB, deep in rock, etc), but it seems the ammonium to nitrite bacteria are kind of everywhere and extremely efficient.

I think the reason that ammonium might not be used as a nutrient source is that it just never even gets to the coral even if it's the preferred food source.

 

[Turtlesteve]

I don't have an opinion as to whether dosing N / P or feeding more is advantageous, but I will note that my tank seems to naturally drift to ultra low nutrient levels without dosing. To maintain N and P I either need to dose them, or intentionally overfeed. The latter makes me nervous, for some reason, but perhaps it shouldn't. I just had P bottom out for the 2nd time and I have not found the right feeding schedule to keep everything where I want it.

Steve

 

[Justfebreezeit]

I don't have an opinion as to whether dosing N / P or feeding more is advantageous, but I will note that my tank seems to naturally drift to ultra low nutrient levels without dosing. To maintain N and P I either need to dose them, or intentionally overfeed. The latter makes me nervous, for some reason, but perhaps it shouldn't. I just had P bottom out for the 2nd time and I have not found the right feeding schedule to keep everything where I want it.

Steve

What are you using to remove P? And are you using a Hanna ULR to test it? In my experience unless the tank is new and finding equilibrium P won't hit actual zero unless you are using something like GFO or lanthanum Chloride, or carbon dosing.

Just curious.