Dosing Potassium Nitrate

[jservedio]

EDIT: Please note that this guide was made back in 2014 and there is no longer a need to make your own Nitrate dosing solution. Every major additive maker now has Nitrate and Phosphate solutions in their lineup that are safe and effective. Spectracide is a stump remover, does not use lab-grade chemicals, and contains impurities which may harm your reef if used over the long term. Back in 2014 we had no choice but to DIY Nitrate and Phosphates solution from stump remover and we didn't even have the option of buying food or lab grade chemicals right off of Amazon back then - you have a choice now. Please choose wisely...

 

--

 

For the past year or so, I have been unable to register even 0.2ppm of nitrate on my Salifert test kit (verified by Red Sea Pro) which has led to paled out, nutrient deficient acros if I slack on feeding and the occasional cyano outbreak when phosphates get above 0.06ppm or so - a truly nitrogen deficient tank. Very heavy feeding definitely works to color up my acros, but it also creates a ton of phosphates, which in turn required a ton of GFO - which was never able to get things back in balance. The easiest way for me to get things back in balance (near the Redfield Ratio) was to manually dose nitrates. With around 0.04ppm of Phosphate, I am shooting for 1ppm of Nitrate (0.64ppm according to Redfield Ratio, but I want a little extra to tip the tank to hopefully being phosphate limited).

 

There have been tons of threads about the benefits of dosing nitrate to remove phosphate and get things back into balance so I won't get into it here, but nobody has specificially laid out HOW to dose it and HOW MUCH. I decided to chose Potassium Nitrate as my nitrate source since it is 1. Readily available and 2. an incredibly simple molecule.

 

My source of Potassium Nitrate is from Spectracide Stump Remover - which according to the MSDS is 100% pure prilled KNO3 and has been successfully used by other reefers with no adverse effects. I picked mine up at Menards for under $6, but I believe Lowes also stocks it and Home Depot can have it special ordered if not already in stock.

 

Now comes the tricky part - how much do I dose to get my desired outcome? My goal was to create a solution where 1ml would increase 1 gallon of water by 1ppm. Here is how to do that:

 

1. Crush up about 1/2-3/4 TSP of the Potassium Nitrate beads into as fine of a powder as you can (we want 1/4 tsp of powder) with a mortar and pestle or the back of a spoon.
2. Measure out 423ml of RODI (400ml will work fine) - the more accurate you are the better it will turn out.
3. Mix 1/4 tsp of the fine powder into the RODI - it should dissolve very easily.

That's it! You now have a solution that will increase 1 gallon of water by 1ppm of nitrate by adding just 1ml of solution.

 

Here is the math/logic that underlies the above recipe:

• KNO3 is 2.1 grams per cubic centimeter in density.
• The Nitrate Ion comprises 62% of the KNO3 molecule by weight
• 1/4 tsp = 1.23cc's
• 1 gallon = 3.79 liters
• 1ppm = 1mg/Liter
• 1/4 tsp of KNO3 = 2,583mg
• 1.62mg of KNO3 = 1mg of Nitrate
• 2,583mg of KNO3 = 1,601mg of Nitrate
• 1,601mg of Nitrate = 422.5 ppm in 1 Gallon of Water
• 2,583mg of KNO3 in 422.5 ml of Water is 1ppm of Nitrate per Gallon per Millileter

 

I am at 1ppm currently and I am going to continue to dose this on a weekly basis after I do my water changes to maintain a nitrate concentration of 1ppm, if my phosphate holds steady at 0.04ppm. If it drops, I will shoot for a nitrate reading of exactly 25x what my phosphates are (according to the Hanna ULR). I will update this thread accordingly every couple of weeks to report progress.

[jservedio]

Note about Potassium: Some people have worried about Potassium Nitrate as a source of nitrates since it also raises potassium and they were concerned they could be overdosing their potassium. However, the amount it is raised is completely negligible! Natural potassium levels in seawater are over 200ppm and some of our salt mixes have close to double that. In order to just raise your potassium by a SINGLE ppm, you would have to increase your nitrates by 2.5ppm since potassium accounts for less than 40% of our solution. Since we are only increasing our nitrates by half this or less, the effect on potassium doesn't matter one bit.

 

Note about Ca, Alk, and Mg: If you have a truly nitrate deficient tank like myself, when you increase your nitrate to detectible levels, in addition to seeing improvements in color, your growth will increase, so you will likely have to adjust your dosing. When you do this, I would suggest going back to testing twice a week for the next month or so. If your tank isn't truly nitrate deficient, your growth won't change at all.

[GlassHouse]

Very thorough and great information!

[jservedio]

Well, Well, Well....

 

Since taking my GFO reactor offline about 3 weeks ago, my phosphates have slowly risen from 0.02ppm up to around 0.07ppm in a little over a week and peaked there, while my Nitrates were steady at 0. Not even the slightest tint to the Salifert low range Nitrate kit which would indicate between 0 and 0.2ppm.

 

The other day was the first time I dosed nitrate in an orderly fashion measured out and dosed exactly 0.5ppm to my tank. In just over 36 hours, while I am still unable to read 0.2ppm nitrate (thought it is definitely over 0), my phosphate dropped literally overnight to 0.042ppm (14 ppb phosphorus) from 0.073ppm (24 ppb phosphorus) using the Hanna ULR checker. I double checked both results to ensure there was no error - and the drop in phosphate happened.

 

Interestingly, my skimmate output close to doubled over the past 24 hours, so I wonder what is going on at the bacterial level.

 

Clearly, dosing nitrate is very effective at reducing phosphate IF your tank is nitrate limited and mature!

 

While this is just confirming many other peoples results, my main concern is the color of my acros - phosphates under 0.1ppm don't bother me and I have never seen phosphates that high before, ever. This is my real goal and I will continue to update. I do wonder though if phosphates will drop below what the ULR can detect.

 

Just added another 1.0ppm of nitrate to the tank and will continue to add 0.5ppm per day until it stops being immediately processed and I can register 1/2 ppm on my test kit.

[dillct]

This calculator is helpful for those using a dosing pump.

 

http://www.theaquatools.com/fertilization-calculator

 

I've been using the stump remover for some time now to help lower phosphates. My only recommendation is that if you also carbon dose, you must watch that you don't trade one problem for another (zero'ing out your phosphates). Take it slowly.

[xlzerolx]

Good topic.

I usea combo of biopellets and prodibio digest and my tank is now at zero nitrates (Set up 2 months) and I can see the colour returning to some of my browned out sps. I want to slowly bring the nitrates up to 1ppm and keep it there as I do not want them turning a pale colour. Most people say feed more, but that's not a very accurate way of figuring out how much you have to feed.

How much nitrate would you recommend adding per day to start? 1ppm , or lower? I am thinking it would depend on how much the bacteria on your biopellets consume right? Should I wait until my sps have completely coloured up before dosing the nitrate?

[jservedio]

This calculator is helpful for those using a dosing pump.

 

http://www.theaquatools.com/fertilization-calculator

 

I've been using the stump remover for some time now to help lower phosphates. My only recommendation is that if you also carbon dose, you must watch that you don't trade one problem for another (zero'ing out your phosphates). Take it slowly.

Cool calculator! The only carbon I am dosing is incidental - which comes from the extra carbon molecules left over from creating Calcium Acetate from Kalk + Vinegar. I would imagine the vast majority of my carbon, just as my phosphate, comes from feeding.

 

My goal isn't to remove phosphates, since they are already low and I have never had a problem with them - having them get even lower is just incidental. However, having no phosphates is better than having no nitrates, at least for me, because adding phosphate is as simple as adding food.

 

I don't know if it is my food, but no matter how much I feed I have never been able to register nitrates for a very long time. And it isn't just algae taking them up, because I haven't had an algae problem since I lost my nitrates - however I get cyano like crazy when I start dumping massive quantities of food in.

 

The purpose of nitrate for me is specifically to get even better color out of my acros.

[jservedio]

Good topic.

I usea combo of biopellets and prodibio digest and my tank is now at zero nitrates (Set up 2 months) and I can see the colour returning to some of my browned out sps. I want to slowly bring the nitrates up to 1ppm and keep it there as I do not want them turning a pale colour. Most people say feed more, but that's not a very accurate way of figuring out how much you have to feed.

How much nitrate would you recommend adding per day to start? 1ppm , or lower? I am thinking it would depend on how much the bacteria on your biopellets consume right? Should I wait until my sps have completely coloured up before dosing the nitrate?

 

If you had browned out acros which are now coloring up, you probably aren't nitrate limited. If you aren't nitrate limited, dosing nitrates is just going to give you algae.

 

Also, I don't think dosing nitrates would be a good solution for you since your nitrate deficiency is caused by something you are doing. If you can lower your biopellet volume and increase nitrates, that is a much better route. Unless you absolutely need to be dosing nitrates, it probably isn't such a good thing. I am hoping I only need to get things back in balance and be done with dosing it. I have no biopellets, no carbon dosing, no GFO, and only a tiny bit of carbon to keep the water clear - my only filtration is the skimmer and it is running super dry - I truly have no filtration to "cut back on."

 

Also, unless you are testing your nitrates with a Salifert or Red Sea Pro kit (or something that has a couple steps below 1 ppm), I wouldn't trust being at 0 or even being nitrate limited.

 

Note: I see looking at your build your tank is new. I would be really worried about adding nitrate to a tank that isn't a year old or more. I don't know if my experience is different form others, but the older my tank gets the better it gets at processing nutrients - if I had dosed nitrates just a year and a half ago, I believe my tank would have been covered in algae (not that my tank needed nitrates back then since I had quite a bit).

[xlzerolx]

If you had browned out acros which are now coloring up, you probably aren't nitrate limited. If you aren't nitrate limited, dosing nitrates is just going to give you algae.

 

Also, I don't think dosing nitrates would be a good solution for you since your nitrate deficiency is caused by something you are doing. If you can lower your biopellet volume and increase nitrates, that is a much better route. Unless you absolutely need to be dosing nitrates, it probably isn't such a good thing. I am hoping I only need to get things back in balance and be done with dosing it. I have no biopellets, no carbon dosing, no GFO, and only a tiny bit of carbon to keep the water clear - my only filtration is the skimmer and it is running super dry - I truly have no filtration to "cut back on."

 

Also, unless you are testing your nitrates with a Salifert or Red Sea Pro kit (or something that has a couple steps below 1 ppm), I wouldn't trust being at 0 or even being nitrate limited.

 

Note: I see looking at your build your tank is new. I would be really worried about adding nitrate to a tank that isn't a year old or more. I don't know if my experience is different form others, but the older my tank gets the better it gets at processing nutrients - if I had dosed nitrates just a year and a half ago, I believe my tank would have been covered in algae (not that my tank needed nitrates back then since I had quite a bit).

 

That make sense. I'll keep things going the way they are. I actually did cut my biopellets in half when I hit zero nitrates about 3 days ago (I thought I'd give the old vodka dosing methodology a shot). I am using the salifert nitrate kit and it is reading zero, and so are my phosphates. I am only using around 30 mls of biopellets right now.. Maybe I should add another fish after a month just to add a little more bioload if things start getting pale.

 

The Sps were browned out from being in a less than perfect holding tank. I am now learning that Alk stability is the key to sps clouring up. I wasn't disciplined enough before to believe it! I always wanted to change things around.

 

Thanks for the advice!

[jservedio]

That make sense. I'll keep things going the way they are. I actually did cut my biopellets in half when I hit zero nitrates about 3 days ago (I thought I'd give the old vodka dosing methodology a shot). I am using the salifert nitrate kit and it is reading zero, and so are my phosphates. I am only using around 30 mls of biopellets right now.. Maybe I should add another fish after a month just to add a little more bioload if things start getting pale.

 

The Sps were browned out from being in a less than perfect holding tank. I am now learning that Alk stability is the key to sps clouring up. I wasn't disciplined enough before to believe it! I always wanted to change things around.

 

Thanks for the advice!

 

Be careful mixing solid carbon dosing with liquid carbon dosing. The key to success with SPS isn't necessarily low nutrients, but rock stable parameters, feeding your tank plenty. and providing sufficient lighting (but not overkill for your nutrient levels). You are on the right track, but just don't overdo it. Pick one method to keep nutrients under control and stick with it - the more you change it the less stability you have.

 

As for the Salifert phosphate kit - don't trust it. I would definitely shoot for 0 on that because it normally reads 0 all the way up to around 0.1ppm. However, that is their only kit that isn't high quality and fairly accurate.

[xlzerolx]

Haha, that didn't come out right

I am only using biopellets. I am just following the vodka procedure that when your nitrates hit zero you cut the vodka dosing in half to a maintenance dose. What I meant was I have cut my biopellet volume in half.

[jservedio]

Well it's been just about a week since I started paying attention to exactly how much nitrate I was dosing (it turns out I was barely dosing anything before) and it has been pretty dramatic. I have dosed the equivalent of 7ppm into the tank over the past week which allowed me to see nitrates for the first time in over a year - thought it wasn't quite up to 0.2ppm in the water column. I have been testing phosphates as well every couple of days and I am now down below 0.03ppm (9ppb phosphorus) and because of this I have been feeding double my normal amount.

 

Since I started dosing nitrates, I have been feeding spectrum pellets 2x daily, Larry's Reef Frenzy Nano every 3 days (dime size) for the fish, and target feeding Limpet's coral blend 2x weekly (equivalent of a "half-cube" if it were mysis).

 

As for my stated goal of coloring up my acros even more since they have been a little faded out due to lack of nutrients, it is definitely working and was almost immediate. My ORA Joe the Coral has always has it's beautiful blue tips, but the base was always gray - in less than a week I can see the green already coming in at night under heavy actinic lighting. Same with my ORA Pearlberry which was super pale blue with just dark blue growth tips - it is now darkening a bit. The only other one that was dramatically faded from lack of nutrients was my JF Sour Twist colony which was the worst - it looks like it is getting a little darker and a couple branches are seeming to get purple tips again, but I have a feeling that one is going to take much longer because of how pale it was. Nothing else was really pale, but it seems things may be getting even better. I am very optimistic and will continue with this current dosing/feeding schedule.

 

Why do I think it is working? Simple: more balanced nutrient levels and a MASSIVE amount of food in the water column without destroying water quality. While I am dumping in tons of carbon and phosphate with food, because I am dosing nitrates at around 1ppm/day the tank isn't limited by them anymore and is able to process everything the corals don't use.

 

Will this work for you? Maybe, but probably not. If your tank is mature and heavily nitrate limited, dosing potassium nitrate can be a magic bullet. If not, well... you will get horrid algae.

[jservedio]

I've continued dosing KNO3 on a daily basis at a rate of 10ml 2x daily every single day (1ppm for my volume) and I am finally testing 0.2ppm of nitrates and my phosphates vary between 0.02ppm and 0.05ppm depending on the day due to the heaps of food I dump in almost daily. I have had some minor cyano for the past couple months since I've moved and it seems to be finally breaking - but that may be unrelated.

 

Colors continue to improve. My Miyagi Tort looks better than I have ever seen it - it's more colorful than it was even in the awesome SPS tank I got it from. The others are continuing to slowly improve in color further. The best way to describe the improvements is that the colors are more rich. While everything was colorful, they were more pastel colors and they are starting to become much more deep.

 

The only acro I had that had poor color before I started, my JF Sour Twist, just began to show color in the past couple of days - a yellow sheen is starting to shine through the bleak white it had been and all of the tips have a faint purple! It looks like this working for sure.

 

I have some more acros coming next week from one of the best acro tanks in the country and I think that will be an even better test of whether this is working. I am hoping everything retains it's color.

 

I will continue to update this thread every couple of weeks as things improve, level off, or get worse. I want to keep track of this long term since I haven't found any threads doing that in any detail.

[jservedio]

Well it's been over a month and for the past 2 weeks or so I have cut back my Nitrate dose to just under 1/2ppm/gal per day into the tank with the nitrates in my tank hovering between 0.2ppm and 0.5ppm with my very heavy feeding schedule. I have noticed that when I don't dose nitrates my skimmer is much less effective, yet when I dose nitrates, I have about 2oz of heavy, nasty, black sludgy skimmate within 24 hours. Also, I am running a light amount of GFO for exactly 3 hours per day right after feeding (3tbsp) on a timer and they are holding steady between 0.02ppm and 0.05ppm depending on how big the chunks of frozen I break off are and how long after feeding I test.

 

Color in my acros is also continuing to improve for the few stubborn ones in my tank and I was recently very, very surprised with a blue table I have in the tank. It has always been a royal-blue color for the past 9 months and I got a few new growth tips coming off some branches that are an incredible, much brighter blue than I have ever seen out of that acro. Also, some of the more stubborn ones that bleached during AEFW last year and were slowly, slowly coming back seemed to speed up quite a bit and now under white light I can see the highlights coming through. There is only one brown acro on my rockwork and only 3 frags on my rack out of a total of 28 acros in my tank. I know the stress from the move this summer played a part in the effect I am seeing, but the nitrates DEFINITELY seem to be helping - if not only with teh color, definitely with keeping phosphates and cyano in check.

 

As for the single concern people have had with potassium nitrate - an increase in potassium - I can confirm it is a complete non-issue. Over the past month my potassium has held steady at right around 415ppm and has not been trending up. The Red Sea Pro test kit for Potassium is very complex, so there is some error, but there is definitely not an upward trend.

[DangerousD]

Dosing this for the first time. Do you still dose this product?

[amphipod]

Fertilize your corals

[hypostatic]

Justin Credabel gave a talk at MACNA, and he apparently doses K:

 

 

EDIT: It's about 20m in in case you want to skip to it

[brad65ford]

wow great video watched it twice

[jestep]

Revisiting this older thread. I'm starting to deal with the exact same issue. Currently dealing with PO4 that begins to cause cyano right around the same level, .06 - .08 on my hanna, I try to keep it between about .02 and .04. Currently feeding 2 - 3 times per day, at least one of those feedings is a frozen cube or a chunk of frozen rods. I have been using GFO to deal with the PO4, but I could theoretically process the additional PO4 without having to use GFO which would save a lot of time and cost, KNO3 is cheap, GFO is not so much...?

 

Your first post basically summarized exactly what I had going through my head and what I'm measuring in my tank, which is essentially completely undetectable NO3. I even doubled my reagent on the same volume test and cannot register NO3, this should be 0 to a resolution of something like 20 PPB, which is ridiculously low.

 

Anyway, I wanted to see if there is any first hand experience with this method over long term.

[gotboostedvr6]

How would one substitute Sodium Nitrate for Potassium Nitrate? Is it 1:1? 

[DevilDuck]

46 minutes ago, gotboostedvr6 said:

How would one substitute Sodium Nitrate for Potassium Nitrate? Is it 1:1? 

I use this calculator http://www.theplantedtank.co.uk/calculator.htm

 

[mcarroll]

🧟

 

A Nitrate Dosing Calculator For Better Tank Health (And Better Coral Color!)

 

 

[jservedio]

On 3/11/2021 at 10:20 PM, gotboostedvr6 said:

How would one substitute Sodium Nitrate for Potassium Nitrate? Is it 1:1? 

 

On 3/11/2021 at 11:06 PM, DevilDuck said:

I use this calculator http://www.theplantedtank.co.uk/calculator.htm

 

 

On 3/12/2021 at 10:42 PM, mcarroll said:

🧟

 

A Nitrate Dosing Calculator For Better Tank Health (And Better Coral Color!)

 

 

I haven't responded to this thread in years, but I would very strongly recommend NOT using Spectracide (or similar products) to create your own DIY nitrate dosing solution!!! Please keep in mind that I wrote this back in 2014 when there were no nitrate or phosphate dosing solutions produced for use in aquariums. We had to make our own and this was the best we had available - but that is no longer the case and hasn't been the case for several years now!

 

Unless you live outside of the US, Canada, EU, etc. where you don't have access to high quality reef additives, please do not use stump remover anymore and if you do have to, only use it for the short term. Spectracide absolutely has impurities in it and unless you know how to remove them, please stick to the Nitrate dosing products that are extremely widely available, cheap, and effective.

[DevilDuck]

9 minutes ago, jservedio said:

 

 

 

I haven't responded to this thread in years, but I would very strongly recommend NOT using Spectracide (or similar products) to create your own DIY nitrate dosing solution!!! Please keep in mind that I wrote this back in 2014 when there were no nitrate or phosphate dosing solutions produced for use in aquariums. We had to make our own and this was the best we had available - but that is no longer the case and hasn't been the case for several years now!

 

Unless you live outside of the US, Canada, EU, etc. where you don't have access to high quality reef additives, please do not use stump remover anymore and if you do have to, only use it for the short term. Spectracide absolutely has impurities in it and unless you know how to remove them, please stick to the Nitrate dosing products that are extremely widely available, cheap, and effective.

 

Thanks for the update! I'll stop recommending it.

 

 

[jservedio]

1 hour ago, DevilDuck said:

 

Thanks for the update! I'll stop recommending it.

 

While the Spectracide MSDS sheet says it 100.0% Potassium Nitrate, the granules have at a minimum potassium hydroxide, sodium hydroxide, potassium carbonate and ammonium nitrate as impurities. None of these are damaging for a reef (in very small quantities...), but those are just the ones we know about because of the extensive testing the model rocket community has done over the past few decades. The reefing community has not done similar research for the impurities that may hurt our systems I'm aware of.

 

Also, MSDS only needs to list impurities if they are over 1% by weight or greater than 0.1% if they are carcinogenic or damaging to humans. Basically, regular impurities aren't listed in the MSDS so you really have no idea what you are getting when it's not food or lab grade reagents.

 

Even chemists like Dr. Randy Holmes-Farley don't suggest using Spectracide and suggest instead using food-grade NaNO3 instead of KNO3 if you are going to DIY it specifically because of impurities and quality control. You couldn't just order ultra high quality chemicals off Amazon back then, so stump remover was literally the best we had.

 

Just buy the good stuff directly from companies like Brightwell, ESV, Seachem, Red Sea, etc. Unless you are going to be using a TON of it, there is no reason to DIY it anymore and if you are going to DIY it, buy food-grade or better NaNO3 and skip the stump remover...