Nitrate DOSING?

[Brooks]

If there is already a thread about this, I apologize for the redundancy.

Nitrate Dosing is something I would've never thought of. EVER. For years the stigma has always been to keep your tank extremely clean; carbon dosing, GFO, etc. etc. No nitrates, no phosphates, no... anything! Well, times have most certainly changed! I would love to hear thoughts about this, and see if there is anyone else here locally who has given this thought.

I highly suggest reading the information on R2R before diving into any decisions.

Here is my synopsis after reading over 39 pages of information and people's experiences using this method:

1. Corals need "food," to survive. Food = NO3 & PO4.

2. Nitrate levels of 2-5ppm & Phosphates of .02ppm - .08ppm (ideally .02ppm) = better coral health, coloration and growth.

3. Begin dosing Nitrogen directly into your system. Spectracide Stump Remover = KNo3 (Potassium Nitrate). 2 tbs of spectracide x 2 cups of water. Mix thoroughly and stir until clear. Store in air-tight container for later use.

4. Dose accordingly, starting slowly at 5-10ml (especially for smaller tanks) until your NO3 levels begin to rise. For many who use GFO, Carbon, and other sources of NO3 & PO4 removal will of course have to dose more, and more often as your system eats it up faster. Its all a balancing act, and everyone will have different dosage requirements for their own tank. It is not quite a proven science, but I'm definitely going to give it a whirl!

People have been using this method, and it seems to be doing great things. Please read the below for more detailed information. I have also included links to 2 threads on R2R.

Ok this writeup is just something I will do to reference everyone who has ulns (ultra low nutrient systems).

Constantly I am asked in mails, forums, etc how to solve this issue. I will explain how I came up with this solution and how you can overcome this disheartening problem.

For this post I will go over the acronyms and what I mean when I use them.

po4: phosphate / phosphorus
no3: nitrate / nitrogen
C: carbon
ulns: ultra low nutrient system
lns: low nutrient system

ulns has been used so much I dont know where to begin with what it "really" is. However for the sake of this article it means that you have a no3 and po4 deficit.
What is a no3 and po4 deficit you ask? It means that if you were to dose phosphorus and nitrogen in to the system that it would eat it up and get you down to 0 ppm without any water changes.

Contrary to popular belief. A REAL 0 ppm no3 and po4 reading is a major problem. You will witness corals pale, turn bone white, while people tell you to feed more or turn down the lights. There is some truth to this but let us get to the heart of the matter shall we?

A long time ago some old guy (who is gone now) discovered something called the redfield ratio. (google this for more info as i will do a synopsis)
Redfield ratio and all it's spin-off theories state that photosynthesis occurs in the ocean at a near universal rate of 106C:16:no3:1 po4.

Now while I wont get in to the deviations of benthic macroalgae or of other life. It is a REAL GOOD IDEA to use it as a guideline.

So what does that mean to the aquarist?
Well it means if you do not have no3, or po4, or carbon.... bye bye corals. They have nothing to photosynthesize. They cant use alternative fuel like lithium or plutonium to synthesize... so they pale. The zooxanthellae which is a dinoflagellate is the same as algae. (in layman's terms). They need it. And you probably have just enough no3 and po4 to get them hold on for dear life.

How do we solve it?
Well we know that po4 is the LEAST needed for photosynthesis. So getting it is easy to come by. Even by my tank which sucks up nutrients like a sponge. Every time you feed, touch, or even look at the tank, po4 will be in the water column. The only exception to this is a GFO overdose. If you are overdosing GFO you will basically have nothing for it to photosynthesize. Remember the redfield ratio of 16no3 to 1po4? yeah... it's a marriage. Need em all buddy. So make sure you have some.

I have observed that po4 measurements of .02ish is optimum. However up to .08 is fine as well. (although some life will get irked)

no3 should be around 2ppm - 5ppm for optimal coral coloration. If 2ppm or below is observed for longer than a week, corals will pale. Mine will pale within 72 hours. It is essential to keep no3 above po4 to prevent nuisance algae like GHA and to not get in to the cyano trap of po4 being greater than no3.

How do we avoid this? Well we can use sodium nitrate (the byproduct is salt and relatively safe) or potassium nitrate (byproduct can be potassium and possibly overdose). I choose the latter because I do have a potassium kit and it is readily available within Seachem's Flourish Nitrogen formula. Care should be taken and warning should be given. I have not observed any detrimental effects, however if you want to go the powdered "pure" route, you can look up salt peter or spectracide stump remover from lowes which is essentially the same stuff.

Alkalinity has been also an issue with ULNS. I have observed alk above 8 to make my birdnest recede and even RTN if approaching the 9s. Many a birdnest I have lost wondering what my issue was until I dropped alk down to the 7s. I personally maintain alk between 7.2 and 7.8 at all times. At 8 or above... my sps get irritable. This could also be the issue with ulns and high alk where burnt tips occur due to the skeletal formation of calcium carbonate forming faster than the photosynthetic ability of the coral via the zooxanthellae.

LIGHT:
If you have strong strong light and you have no nutrients, you are really just stressing the heck out of the sps because there is nothing to photosynthesize. You need these nutrients, and the less you have, the lesser your light should be discourage photosynthesis. We are always told more light, more par, more pur, but in the end, if the building blocks are not there... degradation occurs. There is no reason to have a 1000 hp engine, if you have no gas to go somewhere.

ARTICLE ABOVE:

http://www.reef2reef.com/threads/help-my-sps-are-paling-and-i-dont-know-what-to-do.210035/

DOSING GUIDE:

http://reef2reef.com/threads/potassium-nitrate-spectracide-stump-remover-dosing-steps.215730/

Edited February 18, 2016 by Brooks

[FarmerTy]

Hey Brooks,

I actually did it last year when I ran some experiments with controlling nutrient levels with biopellets, GFO, and dosing Spectracide Stump remover. I played with being able to adjust my nutrient levels on the fly and to see if I could use biopellets as a sole source of nutrient removal by dosing additional nitrate to the system to force the biopellets to remove even more phosphate in my system (as carbon dosing is heavily skewed towards nitrate removal), hoping to remove GFO altogether.

While the ability to control nutrients was achieved, the ability to remove biopellets entirely never really manifested. At a certain point, I could have continued to dose even more nitrates to the system but it seemed like a lot more work than it was worth, not to mention adding the extra element of human error and potentially overdosing nitrates. I thought it safer and more practical to stick with my biopellets and GFO regiment and so the experiment ended.

Funny you mention this, because when I put my corals back in the tank about 2 weeks ago, I noticed that the colors were pretty faded. It correlates with my decreased nitrate level as I'm currently reading about 0.25 ppm of nitrate in my system using the Red Sea Pro Nitrate test. I was planning on dosing my nitrates back up again (just have to find my old bottle of stump remover) and get it back in the 5-10 ppm range that was treating me so well before. I'll probably only maintain this for a couple weeks because on March 3, my tank will have hit the 76 days of being fallow and I'll slowly start reintroducing fish. At that point, the bioload associated with the fish and feeding them should be able to maintain my nitrates at the 5-10 ppm that I was achieving prior with a full fish population.

If I had to guess, 70% of the tanks in Austin probably don't need to be thinking about dosing nitrates. It's only when you're being really aggressive with nutrient removal do you need to think about adding nitrates back into the system. The other thing to think about is just because you're reading 0 on your nitrate kit, doesn't mean you don't have a nitrate problem. If you see excessive algae in your system and you're reading 0, the algae is really uptaking all your nitrates... so if you start dosing nitrates because you think you're deficient, you'll see an algae bloom in the tank and your nitrates STILL may read 0.

Either case, I'm glad you posted it as information like this helps to further our knowledge of reef keeping and brings the discussion to ARC. I caution though that most will probably never need to do this so make sure you do your research before you start dumping stump remover into your system.

[Brooks]

Hey Brooks,

I actually did it last year when I ran some experiments with controlling nutrient levels with biopellets, GFO, and dosing Spectracide Stump remover. I played with being able to adjust my nutrient levels on the fly and to see if I could use biopellets as a sole source of nutrient removal by dosing additional nitrate to the system to force the biopellets to remove even more phosphate in my system (as carbon dosing is heavily skewed towards nitrate removal), hoping to remove GFO altogether.

While the ability to control nutrients was achieved, the ability to remove biopellets entirely never really manifested. At a certain point, I could have continued to dose even more nitrates to the system but it seemed like a lot more work than it was worth, not to mention adding the extra element of human error and potentially overdosing nitrates. I thought it safer and more practical to stick with my biopellets and GFO regiment and so the experiment ended.

Funny you mention this, because when I put my corals back in the tank about 2 weeks ago, I noticed that the colors were pretty faded. It correlates with my decreased nitrate level as I'm currently reading about 0.25 ppm of nitrate in my system using the Red Sea Pro Nitrate test. I was planning on dosing my nitrates back up again (just have to find my old bottle of stump remover) and get it back in the 5-10 ppm range that was treating me so well before. I'll probably only maintain this for a couple weeks because on March 3, my tank will have hit the 76 days of being fallow and I'll slowly start reintroducing fish. At that point, the bioload associated with the fish and feeding them should be able to maintain my nitrates at the 5-10 ppm that I was achieving prior with a full fish population.

If I had to guess, 70% of the tanks in Austin probably don't need to be thinking about dosing nitrates. It's only when you're being really aggressive with nutrient removal do you need to think about adding nitrates back into the system. The other thing to think about is just because you're reading 0 on your nitrate kit, doesn't mean you don't have a nitrate problem. If you see excessive algae in your system and you're reading 0, the algae is really uptaking all your nitrates... so if you start dosing nitrates because you think you're deficient, you'll see an algae bloom in the tank and your nitrates STILL may read 0.

Either case, I'm glad you posted it as information like this helps to further our knowledge of reef keeping and brings the discussion to ARC. I caution though that most will probably never need to do this so make sure you do your research before you start dumping stump remover into your system.

Hey Ty! Glad to see you're a night owl just as I am.

What a GREAT post! Thank you for sharing your experiences with this method. I'm going to (attempt) to elaborate on my thoughts on the matter, and hopefully make sense of everything I've read including your thoughts. PLEASE PLEASE correct me if I'm wrong anywhere - it most certainly wouldn't be the first time . I can use my 2+ year hiatus as an excuse!

There is definitely a lot of reading to do on the subject. I agree that those with algae issues definitely need to assess their specific needs before using this method. Those afflicted with the algal curse like GHA, or worse, cyano, may have higher PO4 and lower NO3. Luckily cyano can be treated (in most cases) by Chemiclean, unlike GHA which is treated well and effectively with nutrient balance and/or manual removal (I always liked my Lawnmower Blenny ).

But what of those who consistently get readings of 0ppm NO3 & PO4, don't suffer the headache of a buildup of algae/cyno, but DO struggle to keep more difficult corals such as SPS alive? With a lighter bioload and little to no excess nutrients, dosing might be a viable solution. Or, reducing their exportation of excess nutrients and increasing their bioload to achieve these results organically. It all varies based on what your specific tank needs are. If I have a heavy bioload, and an lite-moderate method of eliminating excess nutrients, this theory would DEFINITELY not be a good fit for my needs. Perhaps carbon dosing would prove to be more effective if this was my case.

I remember years ago, when I first started diving into the wonderful world of Reef Keeping, hitting that 0ppm mark was AWESOME! After a while, I stopped checking my PO4 and NO3 levels, as I never tested above 0ppm. I also HATED water changes... and still do... so I stopped performing them regularly. Then, I began to notice excellent growth and great PE (mainly in that Sunset Milli colony... I miss that thing). I tested my water and saw the NO3 levels were around 2-3ppm. I inevitably accepted that I wouldn't be able to get them lower due to my increased bioload in a 34g Solana. Heck, the fact that I had a Fuzzy Dwarf Lion who loved ghost shrimp and being hand-fed (my mother really loved that trick) could alone build up NO3 REALLLLY quick. It really wasn't until I began reading these articles and posts that I remembered the "eureka," moment I had so long ago.

Now, I can't say with a great deal of certainty that was the only contributing factor, but perhaps it did play an integral part in the success of my tank.

I'm super glad to hear that you did find success in making your corals happy with this method, even if done while fallow. That shows that the theory behind this methodology is correct! I understand with the reintroduction of fish might eliminate the need to resort to this method again. Especially if you're a heavy feeder. But, what if your nutrient exportation IS so heavy that you begin to get into a dangerously low level of nutrients? Would you begin dosing again, or lean towards something else?

Thanks again for engaging! Hopefully this thread helps some of our members!

Edited February 18, 2016 by Brooks

[FarmerTy]

I think all of your conclusions are on point regarding nutrients in your system. This is the perfect time for TimFish to pop in and say, I told you guys to feed your corals!!!

I think the advance of technology has allowed us to be way more efficient at removing nutrients in our system, and as a whole, the industry is realizing this and starting to go the other way a bit and allowing some nutrients back in. I still aim to keep my nitrates at around 5-10 ppm and my phosphates at 0.03 ppm. My phosphate level is a bit more rigid than I would say most need to aim for, it's just because my tank is SPS-dominant. I'd imagine anything around 0.08 ppm for phosphates is ideal.

I haven't dosed my stump remover yet. I was just thinking about it 2 days ago when I took a step back to look at my corals and noticed how light all my corals look. The colors aren't as deep as they were when my fish were in there and the nitrates were hovering around 5-10 ppm. I plan to soon, but I'll just wait until after the meeting this Saturday at my house in case something goes wrong and everybody has nothing to look at but acro skeletons.

Though I employ a very aggressive nutrient removal strategy, I highly doubt I'd ever have a problem holding some nitrates in there. My fish population leans on the side of borderline excessive, not just heavy fish load but even more than that, so I think I'd be hard pressed to not be able to keep some nitrates in the system. If I somehow can't, I'll just decrease the amount of biopellets I run and that should give me some of my nitrates back.

[Juiceman]

I just feed my fish everyday.... no problems here!

[victoly]

The biggest problem with this method is our inability to a) accurately and precisely measure nitrogen in our water and b) accurately and precisely measure nitrogen consumption by two disparate nitrogen consumers a1) coral *yay* and a2) nuisance algae *boo*. I will say though that from a biological perspective, phosphate is much more scarce and readily consumed. As a result, algae "winning the war" vs coral in terms of consumption is probably much more intimately linked to phosphate concentrations as opposed to nitrate. That's not to say that nitrate isn't limiting or doesn't have an effect, but I would wager that the transient nature of phosphate is much more likely to be the culprit for many of our problems. Getting that ratio of PO4 to NO3 correct may be the main driver here.

[Sascha D.]

I just feed my fish everyday.... no problems here!

+1

[Brooks]

I just feed my fish everyday.... no problems here!

With a heavier bio load and regular feeding, this method is the opposite of what you want to do! ?

Glad the ole' fashion way works for you! It's awesome when you finally hit the perfect balance.

[Timfish]

Oh my goodness! How can I keep anything alive with 5 mg/l PO4 and no NO3!?

I have to agree with Victoly though, with corals sucking up ammonia straight from the water as well as uric acid and amino acids, both organic forms of nitrogen, and even sucking up nitrates if they have to it's impossible to test what's really happening with the nitrogen cycle in our tanks. And considering phosphate is the limiting factor of a corals ability to use nitrate as a food for it's zooxanthellea and when corals have low internal phosphate they become very sensitive to light and bleach easily I'm curious how robust the corals will be and how the tanks are going to look over time dosing nitrates but keeping PO4 low. I would think it as important to track how much and how often corals are being fed along with water parameters to see how food is helping to compensate for low PO4 levels.

[Brooks]

Victoly,

Thanks for chiming in! Glad to see you're still here!!

I've always understood that the amount of N (Nitrogen) is irrelevant in it's basic form. It's importance beings during the nitrogen cycle (nitrogen to nitrite, nitrite to nitrate, then back to N2 which bubbles out of the water column)... and throw ammonia in there somewhere. We can test for it in every (relevant) form aside from its basic elemental state as Nitrogen. Is that correct? I'm hoping so, because relearning this chemistry will make my head HURT!

You've hit the nail on the head in regards to maintaining the perfect balance of NO3 to PO4. Everyone has a different method of doing so. As a general rule of thumb, you PO4 needs to be less than you NO3.

NO3 & PO4 are ALWAYS present in the water column, but if your deficit is so great that you become completely absent of either, your corals will begin to die. With a heavier bio load and increased feeding, dosing nitrates is unnecessary. One can assume that those without algae and bacteria issues, heavy bio loads, and good coral growth have their ways of exporting excess nutrients and balancing things out.

I understand that this method might be foreign and sound strange. Its worth reading into, though. Lets not forget that our hobby is only improved with trials and error; we've all got to be open to new ways of thinking. All in all, the methodology behind this method is proven science in regards to the relationship of nutrients, zoox, and the like. If all else fails, the discussion of this subject will hopefully lead to a much better understanding of water chemistry as it relates to our corals.

Found this on RC while reading... Food for thought.

Most are familiar with balances in calcium alkalinity and magnesium but when dealing with nutrients, particulary NO3 and PO4 the common modus operandi seems to be go for 0. The less the better is mostly true but to a point..

Surface reef waters hold very low levels of NO3, around 0.2ppm and PO4 0.005 ppm Green microalges are known to be limited by levels under .03ppm. Deeper more turbid waters where many lps and leathers live hold considerably more. Even in low level areas the available nutrients are constantly available as upwelling through the reef structure keeps them coming
So how do we deal with balance and nutrient levels in a reef tank when we want to keep a variety of invetebrates and maybe a macro algae refugium too?

Invertbrates are usually termed autotrophic/photosynthetic or heterotrophic/non photsynthetic. The truth is almost all of them are mixotrophic and have some variable level of heterotrophic need for organic carbon.. They can not produce all the organic carbon they need from photsynthesis and need some from food or absortion from the water. They also need a relatively constant supply of phospahte and nitrogen. One of the problems with tactics to remove NO3and PO4 is rapid depletion which in some cases occasions significant coral stress and deterioration..
Reefs are full of food constantly. So called ulns( ultra low nutrient systems ,a common term without precise meaning) are not. Go for zero NO3 and PO4 and then add back elements and ammino acids to make up the loss is the way they work. They might be fine for pastel sps and for folks who like to mange lots of supplements and experiment with them. Many folks like thees approaches,( zeovit systems et al) and enjoy the hobby that way. However, I doubt you can keep many lps growing in them for very long.

The need for organic carbon was discussed in the previous section. The same principles apply to nitrogen and phosphorous. If either are absent the bacteria will not grow and the carbon dosed can just build up. Excess organic carbon is harmful and covert since we don't measure it.
Nitrogen defficiencies are commonly reported but are unlikely to occur in a fed tank.

PO4 deficiencies with heavy adsorbent(gfo, aluminum based adsorbents, et al.) or flocculant ( lanthanum chloride) use may also occur even in a fed tank.

A few folks dose KNO3( potassium nitrate) to correct nitrogen deficiencies. Many more use amino acids which contain nitrogen. I imagine some dose PO4 in some form too but don't recall any such accounts. Food and fish waste do fine for both.

Phosphate and nitrate imbalance:

The bacteria encourage by the organic carbon reduce nitrogen by taking some of it as food along with a proportionate amount of phosphate. However, they also deplete additional NO3 via anaerobic respiration wherein they take the O leaving some of the N to form N2 gas which bubbles out of the tank. This may lead to a situation where some extra low range PO4 is left which can be cleaned up with a little gfo or other remover.

Edited February 19, 2016 by Brooks

[FarmerTy]

Something tells me when I add more nitrates to my system, I'll reach a more harmonic balance of nitrate to phosphate. It's so odd to remove fish and the resulting higher nutrients that come with them, and end up with MORE nuisance algae then with lower nutrient levels in the tank.

I feel like the imbalance is causing the algal growth, not so much the nutrient level itself, even though it's lower. Of course the fish do eat a lot of the algae but I'm also seeing more growth in my sump where it didn't really grow much before and that area was always free of grazing fish.

[jestep]

Revisiting this. Is anyone still playing with KNO3 dosing of any sort?

Short backstory, I have extremely efficient NO3 export and have been dealing with PO4 through the use of GFO. I start getting cyano around .06 - .08ppm PO4. However, my NO3 is completely undetectable. It's undetectable using a Salifert NO3 doubling the reagent on the same volume of water, which translates to a resolution of 20 ppb. It's low.

So my thinking here, is that by dosing KNO3 it would allow a more controlled uptake of PO4 possibly eliminating the necessity to use GFO at all. Obviously this has to be carefully planned and controlled, but presuming the redfield ratio holds true and I don't somehow lose the bacteria necessary to process my NO3 and PO4, the addition of nitrate will allow the system to process the excess PO4. I suspect this comes at a risk of overdoing nitrate and stripping the system of PO4 entirely, but someone correct me if I'm completely off here at least in theory.

[FarmerTy]

Revisiting this. Is anyone still playing with KNO3 dosing of any sort?

Short backstory, I have extremely efficient NO3 export and have been dealing with PO4 through the use of GFO. I start getting cyano around .06 - .08ppm PO4. However, my NO3 is completely undetectable. It's undetectable using a Salifert NO3 doubling the reagent on the same volume of water, which translates to a resolution of 20 ppb. It's low.

So my thinking here, is that by dosing KNO3 it would allow a more controlled uptake of PO4 possibly eliminating the necessity to use GFO at all. Obviously this has to be carefully planned and controlled, but presuming the redfield ratio holds true and I don't somehow lose the bacteria necessary to process my NO3 and PO4, the addition of nitrate will allow the system to process the excess PO4. I suspect this comes at a risk of overdoing nitrate and stripping the system of PO4 entirely, but someone correct me if I'm completely off here at least in theory.

Been there Jestep. I tried to do the same thing but using my biopellets to uptake nitrates and some phosphates, hoping to eliminate GFO use. I wasn't able to do it but that doesn't mean you might not be able to.

I think dosing the nitrates will allow you to use less GFO but in the end, I still think you'll need it.

I've never had an issue with too little phosphates, but I mainly run acros. My last Triton lab test read zero for phosphates and my Hanna Ultra low phosphate meter reads zero as well.

When "they" mention ulns being to low on nutrients and that you need to increase your nutrients, I honestly wish "they" would say just increase your nitrates. My opinion is there is no need to ever increase phosphates. As long as you have some fish and are feeding them daily, you're getting enough phosphates to keep your corals happy. My example is the perfect one... Zero detectable phosphates, I still run GFO, but I feed the heck out of my tank so it gets its daily phosphate dose.

[jestep]

When "they" mention ulns being to low on nutrients and that you need to increase your nutrients, I honestly wish "they" would say just increase your nitrates. My opinion is there is no need to ever increase phosphates. As long as you have some fish and are feeding them daily, you're getting enough phosphates to keep your corals happy. My example is the perfect one... Zero detectable phosphates, I still run GFO, but I feed the heck out of my tank so it gets its daily phosphate dose.

That's really my thinking. I have upped my feeding to about 3 times per day on average, at least once per day is with a frozen which tend to be significant PO4 sources. But, even GFO reduction would be beneficial, I think maybe even desirable for control purposes, but I'm currently at 1 cup per week right now...

I never thought I would intentionally dose nitrates on a reef tank, but a light bulb more or less went off and at least in theory it can solve a lot of High PO4 and NO3/PO4 imbalance issues. I'm glad someone else has at least tried it though but I definitely see potential risks in overdoing it. I did get an extremely accurate doser recently, so might start slow dosing to see where it goes.

The effects should be almost immediate, correct (as in days)? I imagine PO4 uptake is going to be quickly apparent with a moderately accurate baseline and minimal other changes that would affect it.

[FarmerTy]

Wow! 1 cup/week? I use 1.5 cups/month on my 215-gallon! Though I will say that my coral population is probably acting like a good nutrient sponge just by volume and my biopellets are uptaking some of that phosphate as well.

You really don't have to take it slow from my experience. I dosed it up to 5 ppm in a day and maintained it there as best as I could. 10 grams of potassium nitrate to 1 liter of RO/DI water... I dumped in half a liter every 2-3 days if that gives you a reference to go by.

[jestep]

Wow! 1 cup/week? I use 1.5 cups/month on my 215-gallon! Though I will say that my coral population is probably acting like a good nutrient sponge just by volume and my biopellets are uptaking some of that phosphate as well.

Actually a net of 2/3 cup a week, but a lot. I've gone down to a 3 reactor GFO regimen, and doing incrementally 1 cup per week, with the 4th week idle. The idle week allows me to readjust the estimated amount up or down. I started a 4 reactor one to minimize bouncing phosphate, but the 3 reactor method has actually been more stable and less prone to overdoing it.

[FarmerTy]

Have you noticed issues with your phosphate level spiking up and down with each swap of GFO before the multi-tiered reactor setup?

I've always just swapped out once a month and my acros have never had issues with it.

[jestep]

Have you noticed issues with your phosphate level spiking up and down with each swap of GFO before the multi-tiered reactor setup?

I've always just swapped out once a month and my acros have never had issues with it.

I was getting pretty significant bouncing when I was changing it every 4 weeks. I actually tried just increasing the frequency of changing it out, and had trouble with dropping it too low. Then tried adding less on subsequent doses and didn't drop it enough, it was like I was always too low or too high with a single reactor. The multi setup just made it a lot easier all around for me.

Did you have a calculation for the concentration of KNO3 you used for your dosing? Trying to get this all on paper so I can accurately plan a dosing schedule. I calculated I need for my 380 liters of total volume, .62g of KNO3 to increase concentration by 1ppm. This is compensated for molarity.

I'm not sure what the maximum amount I can dissolve in water is going to be, but if I can add 62g to 1L of water, and then dose 100ml per day, it would add 1ppm NO3. If I can get away with dissolving double that, 50ml per day would increase NO3 by 1ppm.

If the brief research I've done on bacteria uptake is close to correct, the N:P uptake ratio is 6:1, meaning I need to increase NO3 by a factor of 6 to facilitate the consumption of 1 factor of PO4. That's something like 300ml of fairly concentrated solution, which is basically why you are able to dump this in your tank without serious chemistry issues.

I've never calculated the total mass of PO4 my tank is producing, so going to figure that out to get a baseline of what I'm actually needing to deal with per month here.

[FarmerTy]

Let me see if I can dig up my notes from when I was nitrate dosing. We just did a huge house cleaning so they may have wandered into the recycle bin.

Its a bit late for me to willingly do calculations but if I get some free time tomorrow, I'll try my hand at it and refresh myself.

[FarmerTy]

All I remember off the top of my head is 10g of potassium nitrate to 1liter of RO/DI water gave me a concentration of 6140 ppm of nitrate. I must have calculated roughly half of that for my tank volume.

[Iyad Aoun]

these articles are key answers to my problems with algae matter.Fighting always with no3 and po4 reaching zeros levels was surely wrong ending up with bleaching and algae growth.Now I am convinced that no3 and po4 should both be present.The real problem is about the real ratio.

Consulting Redfield table if the desired level as commonly admitted would be 5ppm of no3 then amazingly the po4 level should be 0.3 which is enormous.

So here is my question :what would be the desired level of po4 if no3 should be 5ppm

I read lot of articles but no one clearly respected the redfield ratio since the admitted rule of thumb is 5 nitrates for 0.04 as average phosphates which is ten times less phosphates than the redfield chart.

thank you

Dr Aoun-

Lebanon

[Timfish]

Here's some links to research papers.  Low phosphorus and high nitrogen is not a good combination for corals.  When considering  the nitrogen demands of corals all types of nitrogen also need to be taken into account, the dissolve organic nitrogen (DON ) forms of dinitrogen, amino acids and urea and the inorganic forms (DIN) of ammonia/ammonium, nitrites and nitrates.  It shouldn't be overlooked that nitrates are corals least favorite form of N.   We also need to expect species specific responses to imbalances in the C:N:P ratios.

To start with here's a video done by some researchers warning against high nitrogen to low phosphate ratios.
https://ars.els-cdn.com/content/image/1-s2.0-S0966842X1500075X-mmc1.mp4

Context dependant of nutrient loading on the coral-algae mutualisim (nitrate can push it to parasitism on the part of the algae)
https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-1407.1

Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
http://www.indiaenvironmentportal.org.in/files/file/Nutrient%20enrichment.pdf

Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates  (The researchers identified a minimum threashold level of .03 mg/l PO4 at a redfield ratio of 22:1 N:P to prevent damage to the coral)
https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via%3Dihub

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach
https://www.sciencedirect.com/science/article/pii/S0022098111004588

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata
http://jeb.biologists.org/content/214/16/2749.full

Nitrogen Cycling in Corals; the key to understandking holobiont fucntioaning?
https://www.sciencedirect.com/science/article/pii/S0966842X1500075X#fig00

Uptake of free dissolved amino acids by the scleractinian coral Stylophora pistillata
https://jeb.biologists.org/content/211/6/860.long

Urea uptake by the scleractinian coral Stylophora pistillata
https://www.sciencedirect.com/science/article/pii/S0022098105005538

Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution (carbon dosing)
https://www.sciencedirect.com/science/article/pii/S0166445X19307192

Nitrate increases zooxanthellae population density and reduces skeletogenesis in corals
https://link.springer.com/article/10.1007/BF00942117

 

Your experiences seem too have mirrored my own.  I have two threads dealing with nuisance algae where PO4 increased as nuisance algae disappeared.  Here's the links:

http://www.austinreefclub.com/topic/34556-hair-algae-a-case-study/?tab=comments#comment-275433
http://www.austinreefclub.com/topic/39043-hair-algae-a-second-case-study/?tab=comments#comment-325744

 

Here's fig 3 from Shantz and Burkepile's paper linked above.  It should be noted their paper reviewed the data from 208 experiements from 55 or 56 research papers.

[mike klein]

This is a great thread.  Last year i started dosing after my SPS were fading and bleaching even with heavy feeding.  My fuge was never able to sustain algea either until i started auto dosing for nitrate and phosphate.   Now everything is great but I've been getting GHA and Dyno in both my display and fuge.

Question for you dosing experts.. Could this be that I'm not dosing enough or that my ratio is off?  Hanna Phosphate ULR reads .17ppm and my Salifert Nitrate is always a pain to read but I'm almost always at 10ppm according to it.   

Ay ideas on how I can keep the Dynos and GHA in check? 

[victoly]

If your corals are happy I would try to add in biological control. Tangs, foxface, urchins and snails. 

[Timfish]

Biological control is the best way IMO to deal with algae long term.  Short term I may also use manual removal and localized use of H2O2.  One question, how long has it been since you started dosing?  With just about any change to an ecosystem nuisance algae is going to respond faster than corals.  Depending on how severe the problem is it may correct itself with just simple siphoning out nuisance algae with small water changes.  Also keep in mind we can only test for PO4 but reef ecosystems also have organic forms of phosphorus we can't test for.  So along with organic forms of nitrogen what the corals are seeing with respect to the Redfield ratio may be very different from what our tests for nitrates and PO4 show.