Correct NO3 + PO4 Dosing Ratio To Avoid Reducing Either to 0.0?

naterealbig

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Hello,

I am getting a 0.0 Nitrate reading (Hanna, HR) in a newly set up (currently fishless (on purpose)) aquarium. (PO4 reading is 0.03 ppm (Hanna, ULR)).

I am considering dosing nitrate (in the form of NaNO3) to raise NO3 to readable level (just above the stated Hanna error margin). (I am aware that an increase in nitrate can also be accomplished through ammonia(ium?) dosing, but I am trying to avoid any significant amount of ammonia availability to the system for the first/next few weeks.).

I understand (through discussion here but mostly) through my own observations that low levels of PO4/NO3 can(/usually are) reduced to zero if the other is dosed by itself.

To avoid a reduction of current PO4 level (from 0.03) to 0.0, I would like to understand what a reasonable dosing starting point would be for both NO3 + PO4 assuming the dosing will occur simultaneously. (ex: dose enough Na3PO4 to increase PO4 by 0.015 ppm and dose enough NaNO3 to increase NO3 by 0.24 ppm).

I assume there is no 'rule' here, but if there is an educated estimate I could put together that would:

a) increase my NO3 to detectable levels (to say, > 0.5 ppm) whilst
b) preventing my NO3 from falling < 0.03 ppm

I would be grateful.

My (perhaps 'special') logic is saying to start somewhere ~ Redfield ratio.

Which brought up another thought/aside (I suppose for the moment, one that hopefully doesn't completely derail the focus on the next small step I'm trying to figure out); should I take into account carbon in my solution? (Logic is also telling me that if I add carbon, there is the potential to bottom out both NO3+PO4). Or would the recommendation from the pros be to dose carbon, nitrate, and phosphate simultaneously for the best results? (with best being defined as readable NO3, readable PO4, (SPS) corals staying alive, minimizing chance of pest algae/bacteria outbreak in a very new system).

Thank you in advance, and please feel free to point out gross conceptual errors. I always feel like I've got a pretty good handle on aquarium biology, until I start reading through the articles/responses/chatter from Randy, Subsea, Garf, BeanAnimal, and the likes :) ... Promise to have a thick skin along with a willingness to learn (and put in the effort/time/reading if pointed in a direction).
 

Pistondog

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The ratio is not important.
Target 5 to 20 ppm nitrate, 0.1 ppm phosphate.
Some think dosing ammonia (ammonium bicarbonate) is easier for livestock to use, vs nitrate.
You are correct in thinking zero of either is not the best.
 

Randy Holmes-Farley

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There is no ratio that can prevent one from bottoming out for several reasons.

1. N and P are added and used quite independently in a number of processes, in addition to tissue building processes that use both.

2. Even in a given tank with a fixed demand ratio, both could bottom out.
 

Randy Holmes-Farley

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In this case, I’d raise both by feeding more or dosing both.

Curious why you want to avoid this…

but I am trying to avoid any significant amount of ammonia availability to the system for the first/next few weeks.).
 
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naterealbig

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Gents - thanks so much for taking a look, and letting me know your feedback and questions.

The ratio is not important.
There is no ratio that can prevent one from bottoming out for several reasons.

I'm having a tough time wrapping my head around this. (FWIW I'm an M.E. by training, and a supply chain analyst by trade). In my brain I suppose I've modeled this process akin to shortages of parts used to build med devices. We have different quantities of components (some universal, others unique) and we can only build the number of devices equal to the qty of the constrained component, no matter how many of the other components we have. When the previously constrained component becomes available, we are able to build another quantity of devices equal to the qty of the next constrained component. If I know how many of each component we have, and how many components are needed to build a device, and the total number of devices I want to build, then I should be able to calculate the number of each component I'd need to build that device total.

Applying this analogy to a more ambiguous scenario: Let's say I didn't know exactly how many devices I needed to build, but boss says as long as we are manufacturing some qty > 0 each day, we are good. Even if I wasn't sure the qty that I wanted to manufacture, at a minimum I would order the correct ratio of components (say 2 components are needed, and we needed 2 of 1 and 1 of the other to build a device), to ensure we continued to manufacture at some non-zero rate, without ending up with a plethora of one component, or running out of the other.

Is the analogy not applicable to my reef?

1. N and P are added and used quite independently in a number of processes, in addition to tissue building processes that use both.
I'm tracking here, aligns with what I understand.

2. Even in a given tank with a fixed demand ratio, both could bottom out.
I suppose this is the exact point in my commentary at the top of this post that I'm lost. Is there an example you could give that might illustrate your point? (not challenging... trying to understand the piece I'm missing in my 'model'). If there's an article you could point me to that would help me connect the dots (that bio-101-brain could understand) this might be even more helpful.

Let me also add: an 'exact' answer isn't necessary - something 'general' that 'should' work, or even, 'might' work would get me started.

In this case, I’d raise both by feeding more or dosing both.
OK. So do I understand from this along with your note above, that the probability that my PO4 decreases from 0.03 to 0.0 whether I dose N : P at 100:1 or 1:100 or 1:1 is all the same?

I've read over and over here on the forum (usually re: carbon dosing to lower NO3 or PO4) that NO3 reduction stops when the cycle becomes PO4 limited, or vice versa. And to prevent this, one needs to dose the lower of the two, so that reduction can continue. I've observed the phenomenon myself while trying out vodka dosing. I guess I was figuring that if I was trying to do the reverse of this (increase PO4 &/or NO3), that if I simply dosed both I could eliminate potential PO4 or NO3 limitation, and would just need to know what ratio of the two to dose. (at this point I don't really care what the levels are, as long as there is a minimum reading showing on my test kit. I can fine tune the ppm later, once I feel good about my dosing not bottoming-out either of those parameters).

Curious why you want to avoid this…

Skip to the "bold" print if you don't want the full dissertation...

Had to hard reset (completely nuked) my office display (I let Aiptasia take over, and they were about to finish off my remaining SPS) . New BB system started w/ dry rock and (newly purchased, Gulf) live sand, CUC, and salvaged SPS (no fish). Everything is doing great (CUC alive & eating, SPS growing/improving color), and I don't want the effort I've put into resetting the system (testing, dosing, setting up temp holding system, etc, etc) go to waste by having a plague of pest algae and Dino blooms. I imagined/postulated I could limit the severity of the 'ugly phase' by limiting the amount of ammonia (fishless) introduced into the system, whilst providing an environment (maintaining 'Big 3' & trace elements, monitoring/managing PO4/NO3, dosing aminos, and feeding) where beneficial bacteria, microflora/fauna, food webs, have the time, nutritional resources, and real estate to colonize, develop, mature.

At the end of the day, I just noticed that NO3 was at 0, figured there was something in the tank that might need it (especially since it's so new), but didn't want to dose it and throw something else way off.
 
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Randy Holmes-Farley

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At the end of the day, I just noticed that NO3 was at 0, figured there was something in the tank that might need it (especially since it's so new), but didn't want to dose it and throw something else way off.

You are making this far more complicated than it needs to be, and trying to dose a ratio when a ratio is not useful isn't going to help.

Just dose what is low, and watch the other, if it gets low, dose it too. No ratio can always prevent that.

Let me explain that using your own analogy, which is a reasonable, but incomplete one.

Imagine a car factory making one type of car. That is your original analogy. If you put in a 1:4 ratio of steering wheels to tires, neither will ever bottom out unless both are completely used up.

But now imagine the factory makes 3 types of cares which share only some of the parts. One of the added car types uses the same tires but not the steering wheel. The other uses the steering wheel but not the tires.

What ratio of steering wheels to tires should be sent to this factory?

if you do not know the number of each car type being made, there's no way to know, and sending 1:4 is not going to eliminate the possibility of stopping production because one ran out before the other.

The answer comes by keeping track of the levels in the factory and sending what is needed, regardless of what the ratio may be.

In the reef tank setting we have different processes adding and consuming different amounts of N and P, and so there's no ratio added that is the "best". Measure N and P and adjust accordingly. In fact, the majority of people dosing N or P dose only one of them, not both.
 
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naterealbig

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You are making this far more complicated than it needs to be
Surprise, surprise... *having flashbacks of nuclear power training in SC prior to being assigned to the USS Tennessee* "Your nuking it out man!"

Just dose what is low, and watch the other, if it gets low, dose it too. No ratio can always prevent that.
Copy that.

Let me explain that using your own analogy, which is a reasonable, but incomplete one.

Imagine a car factory making one type of car. That is your original analogy. If you put in a 1:4 ratio of steering wheels to tires, neither will ever bottom out unless both are completely used up.

But now imagine the factory makes 3 types of cares which share only some of the parts. One of the added car types uses the same tires but not the steering wheel. The other uses the steering wheel but not the tires.

What ratio of steering wheels to tires should be sent to this factory?

if you do not know the number of each car type being made, there's no way to know, and sending 1:4 is not going to eliminate the possibility of stopping production because one ran out before the other.

The answer comes by keeping track of the levels in the factory and sending what is needed, regardless of what the ratio may be.
All makes sense - thanks for taking the time to put it in these terms.

In the reef tank setting we have different processes adding and consuming different amounts of N and P, and so there's no ratio added that is the "best". Measure N and P and adjust accordingly. In fact, the majority of people dosing N or P dose only one of them, not both.
I'm trying to figure out why I was 100% certain my PO4 would take issue with the NO3 dosing. I realized earlier the idea came from reading through a ton of carbon dosing articles and threads - but unsure of how I tried to apply it to this scenario. Perhaps the concern only comes along with additional carbon availability, with the intent of reducing nutrients... need to go back and review. Ignore me here, just talking.

Thank you for replying, explaining. Will dose the nitrate, continue to test, follow up here to confirm.
 

rishma

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I'm trying to figure out why I was 100% certain my PO4 would take issue with the NO3 dosing.
The ratio idea is a persistent myth for several of reasons, all miss understandings in my opinion. We often do see a correlation between N & P, most frequently when one becomes depleted (sometimes with carbon dosing), among other reasons. More recently observed is phosphate levels impacted if ammonia is added as a source of N.

Targeting acceptable ranges for each and dosing them independently (if needed) is the approach I take, too.
 

lbacha

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The supply chain analogy works here but not in the way you are thinking (all material is part of a greater BOM and you always order everything together). The key to a successful reef it to make sure all needed materials (Nutrients both macro and micro, light, elements, etc) are available at all times but not in too high of a concentration for many. The way we handle this with many elements is testing and No3 and PO4 are no different. As your tank ages and changes it will use more or less of these elements just like Alk/Cal. A minor adjustment of your lights (this could be from you changing them or even from shadowing in the tank could equate to a lowering of growth which equates to less alk use, and then other nutrients.

I treat dosing like a kanban system, if testing (automated or manual) results in a level lower than a set level I have determined then I increase my daily dose amount by a small increment (kanban card amount lol) do this slowly because the other side of the equation is if the tests show the level to be above a limit then I reduce my daily dose amount. Eventually you will get to an equilibrium where you are not changing it often but at the beginning you either need to set a larger range (allow Phosphates to get to 1.5 before adjusting for example). You have to look at PO4 and NO3 and really all your trace elements and even Alk/Cal/Mag separately because your individual tank may use them all at different levels over the course of finally stabilizing.

Since you have a supply chain background and are applying concepts from it to reefing you may want to look into the Reef Moonshiners method of dosing. There are a few others like it as well but the gist is you perform regular ICP tests that tell you the exact levels of everything in your tank. You then dose corrections for items that are low or do water changes to remove ones that are high. You also dose dailies based on the consumption of certain elements in your tank. The ICP testing is not ideal for No3/PO4 since you only test once a month and you really need to test nutrients more often especially in a new tank (once your tank is established the coral and film on the glass will be a visual way to tell how nutrients int he tank are doing so testing is more reactive). For a new tank proactive NO3 and PO4 testing is a must if you want to avoid some of the pitfalls that new tanks can go through.

Hope this help Len
 
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naterealbig

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The ratio idea is a persistent myth for several of reasons, all miss understandings in my opinion. We often do see a correlation between N & P, most frequently when one becomes depleted (sometimes with carbon dosing), among other reasons. More recently observed is phosphate levels impacted if ammonia is added as a source of N.

Targeting acceptable ranges for each and dosing them independently (if needed) is the approach I take, too.

Understood! Thank you!
 
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naterealbig

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The supply chain analogy works here but not in the way you are thinking (all material is part of a greater BOM and you always order everything together).
Ah.

The key to a successful reef it to make sure all needed materials (Nutrients both macro and micro, light, elements, etc) are available at all times but not in too high of a concentration for many. The way we handle this with many elements is testing and No3 and PO4 are no different. As your tank ages and changes it will use more or less of these elements just like Alk/Cal. A minor adjustment of your lights (this could be from you changing them or even from shadowing in the tank could equate to a lowering of growth which equates to less alk use, and then other nutrients.
I'm following.

I treat dosing like a kanban system
Now we're talking!

if testing (automated or manual) results in a level lower than a set level I have determined then I increase my daily dose amount by a small increment (kanban card amount lol) do this slowly because the other side of the equation is if the tests show the level to be above a limit then I reduce my daily dose amount. Eventually you will get to an equilibrium where you are not changing it often but at the beginning you either need to set a larger range (allow Phosphates to get to 1.5 before adjusting for example). You have to look at PO4 and NO3 and really all your trace elements and even Alk/Cal/Mag separately because your individual tank may use them all at different levels over the course of finally stabilizing.
All makes sense above.

Since you have a supply chain background and are applying concepts from it to reefing you may want to look into the Reef Moonshiners method of dosing.
Did I also mention that I'm super lazy? LOL

There are a few others like it as well but the gist is you perform regular ICP tests that tell you the exact levels of everything in your tank. You then dose corrections for items that are low or do water changes to remove ones that are high. You also dose dailies based on the consumption of certain elements in your tank. The ICP testing is not ideal for No3/PO4 since you only test once a month and you really need to test nutrients more often especially in a new tank (once your tank is established the coral and film on the glass will be a visual way to tell how nutrients int he tank are doing so testing is more reactive).
Joking aside, this sounds interesting. Heard the term before but didn't dive in. Assume it's in the same family as Triton? Either way will take a looksee.

For a new tank proactive NO3 and PO4 testing is a must if you want to avoid some of the pitfalls that new tanks can go through.
This was 'pillar' I understood well - PO4 is on point... will work on the NO3.

Hope this help Len
Yes, very helpful Len! Thank you for taking the time to reply (, hand-hold).

Best
 
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naterealbig

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Not that I really think it matters but: dosed NO3 to increase system by 1ppm last night. Measured NO3 + PO4 today:
NO3 = 0.1
PO4 = 0.01 (down from 0.03 day before yesterday (not necessarily because of the NO3 dosing! :) )

Tonight, dose = NO3 to increase by 2ppm and PO4 to increase by 0.03.

Will retest tomorrow.
 

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Not that I really think it matters but: dosed NO3 to increase system by 1ppm last night. Measured NO3 + PO4 today:
NO3 = 0.1
PO4 = 0.01 (down from 0.03 day before yesterday (not necessarily because of the NO3 dosing! :) )

Tonight, dose = NO3 to increase by 2ppm and PO4 to increase by 0.03.

Will retest tomorrow.

Don’t forget that your testers (assuming Hanna checkers though it may have been stated) have margins of error. A Hanna checker “sees” .01 and .03 and 0.00 the exact same. You really need to get PO4 above .05ppm to be sure you’re seeing reliable (enough) changes
 
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naterealbig

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Don’t forget that your testers (assuming Hanna checkers though it may have been stated) have margins of error. A Hanna checker “sees” .01 and .03 and 0.00 the exact same.
Yes, I'm aware. Will apply the same logic to the NO3, although I intend to bring the value up to ~ 5 or so ppm, so a little more wiggle room there.

You really need to get PO4 above .05ppm to be sure you’re seeing reliable (enough) changes
Thanks for fixing me here - I was targeting PO4 ~ 0.03 because I figured actual PO4 would be at least 0.01 but you're right. It's not enough, and allows for no buffer before potentially being back at a true zero. I'll continue dosing at ~ 0.01ppm/day until I'm at 0.05 ppm (adjusting as necessary for 'recovery rate' and then 'SS'). Same with NO3, except 1ppm per day until ~ 5ppm.

Thank you!!
 

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I recently bottomed out my nitrate to 0. I dosed neo nitro 5ml/25g and saw 0.5-1ppm nitrate increase reading everyday til i hit my target nitrate, fed heavy too. Imo following the instruction was just super slow pace.
 

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Hi, as you have a fisheless aquarium with just coral and live rock you can calculate consumption, I would suggest that you raise nitrates and phosphate in a way that you feel comfortable and then allow them to deplete over a period of days. This should give you a daily consumption similar to how you would adjust Kh or Calcium. From there you can just add your daily consumption and adjust as needed.
 

rishma

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Thanks for fixing me here - I was targeting PO4 ~ 0.03 because I figured actual PO4 would be at least 0.01 but you're right. It's not enough, and allows for no buffer before potentially being back at a true zero. I'll continue dosing at ~ 0.01ppm/day until I'm at 0.05 ppm (adjusting as necessary for 'recovery rate' and then 'SS'). Same with NO3, except 1ppm per day until ~ 5ppm.

Thank you!!
fwiw, I found my phosphate lower than I like a few days ago. I dosed enough to add 0.03 ppm, retested the next day, then added another 0.03. All animals seem happy and I move a little more aggressively than you.

i target 0.1 ppm, but I don’t take any action unless it’s outside the range of 0.05-0.15, which it rarely is.

I am sharing this because I think you’ll find a higher target and a target range is more sustainable. It helps compensate for test accuracy and natural variations in the tank.
 
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naterealbig

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fwiw, I found my phosphate lower than I like a few days ago. I dosed enough to add 0.03 ppm, retested the next day, then added another 0.03. All animals seem happy and I move a little more aggressively than you.

i target 0.1 ppm, but I don’t take any action unless it’s outside the range of 0.05-0.15, which it rarely is.

I am sharing this because I think you’ll find a higher target and a target range is more sustainable. It helps compensate for test accuracy and natural variations in the tank.
Thanks for the idea. I wanted to keep it low as I'm trying to avoid a major outbreak of pest algae, but maybe I can shift to targeting raising to 0.07 setpoint, and dose if it gets as low as 0.05. I can always adjust down a little if something pops up. Thank you!
 

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