Nitrate Dosing

[scar79]

Cross post from SPS forum:

http://reefcentral.com/forums/showthread.php?t=2592168

I've been having a heck of a time getting some measurable nitrate into the water column of my relatively young (4 months) 135 gallon reef.

I have very few corals in the tank at this point - 6 sps large frags/small colonies, a few small LPS, and a largish hammer colony. Algae has been minimal after the initial cycle, no refugium, so I really don't have much doing nutrient uptake.

Fish load is moderate:
4 lyretail anthias
2 green chromis
2 snowflake clowns
banggai cardinal
royal gramma
rosey scales wrasse
4" kole tang

I've been feeding frozen (mysis and spirulina brine) 2-3x per day, NLS pellet 1x per day, arctipods in the morning, and at lights out the tank gets a dose of aquavitro fuel, oysterfeast, and frozen cyclops.

The equipment setup on this tank is nearly identical to it's last iteration which was a successful SPS tank. I converted it to a FW planted tank, but quickly grew bored and now its back to an SPS geared setup. Lots of internal flow, lots of light (2x radions and 4x 54w T5), a Bubble Magus Hero 180 skimmer, and a TLF phosban reactor with a small amount of rowa-phos. I like to keep equipment simple yet effective.

One other difference in this iteration is that I've kept the Marine-Pure spheres to my sump that I had been using in the FW setup. I have done some reading in the Siporax thread and wonder if this may be the culprit.

Despite the heavy feedings, I haven't gotten nitrates readable on my salifert kit. Fish are fat and algae is well under control. Phosphates have been around .02-.07.

Three days ago, I decided to experiment. Having come from the planted setup, I still have some potassium nitrate (KNO3) sitting around. I added a bit over 1/8 tsp to the tank (which should have provided me with about 1.2ppm nitrate). I tested before and about 20 minutes after. ALAS! Nitrates of about 1ppm on my salifert kit!! At this time, my PO4 also read .05 on my hanna LR tester.

24 hours later, I tested again. Nitrate 0.5, phosphate .02. 48 hours after that (today), I test about 0.2 nitrate and 0.00 P04. I've noticed no increase in algae growth, or any other noticeable change for that matter. I shut off my phosphate reactor.

I am going to dose KNO3 again and continue to observe.

Please feel free to add any input, observations, or personal experience!

[tmz]

I tweak with sodium nitrate ,a tiny amount( 1 tsp for 650 gallons of water volume every 10 days or so ). This brings the nitrate to a level from undetectable to sub 1ppm but lightly detectable on the Salifert kit. PO4 in my system holds around 0.02ppm to 0.04 ppm with NO3 around 0.2ppm. The KNO3 may bump up the K overtime if a substantial amount is used.

[bertoni]

Dosing nitrate is a reasonable experiment to try. A number of people have been successful with it. I agree that sodium nitrate is a bit safer, at least in theory.

[Newms118]

I tweak with sodium nitrate ,a tiny amount( 1 tsp for 650 gallons of water volume every 10 days or so ). This brings the nitrate to a level from undetectable to sub 1ppm but lightly detectable on the Salifert kit. PO4 in my system holds around 0.02ppm to 0.04 ppm with NO3 around 0.2ppm. The KNO3 may bump up the K overtime if a substantial amount is used.

Where do you get your sodium nitrate? I'm having the same issue with zero nitrate, and phosphate 0.04 - 0.06. Started dosing with NO3PO4X because algae in DT was eating all the nitrate/phosphate and couldnt grow chaeto in the refugium.

[tmz]

I bought a pound or two of it from an online vendor several years ago. I'll see if I can find a link. . I really don't use it much ;not sure there is a major between undetectable NO3 and the small bump I provide from time to time but it seems to make a small differences: it does seem to upgrade some coral colors when and if if paling occurs ; it also drops the PO4 tad ( say from .05ppm to .01 - 02 ppm after dosing; more than 1ppm NO3 will spike nuisance algae,IME.

Found the link:

http://www.dudadiesel.com/search.php?query=%22sodium+nitrate%22

[amcvay1979]

Your ceramic media are for sure where the nutrient uptake is taking place. I wouldn't worry too much about keeping detectable nitrates as plenty of SPS dominate tanks regularly don't detect any Nitrate or Phos for that matter. I've run ULNS for awhile now and I regularly test 0/0 Nitrate/Phos so I just dose amino acids and make sure I'm feeding heavily daily and at least 2 times per week feed the corals a mixture of coral specific foods. It's been working for me. I dose 1 ml of amino's per day and my total tank volume is around 150 gallons.

Kind of a Zeo approach, but if you control what the corals use for growth while limiting Nitrate and Phosphate you'll end up with a very clean tank and free of algae. Plus your corals colors will really pop. Just my $.02 I do dose some Nitrate every once in awhile if I can't get my Phos below .08 and it won't budge I'll add some Nitrate (stump remover) and it'll be gone the next day.

[amcvay1979]

Also, if you want to get your nutrients to register, you can try turning your skimmer off for a few hours per day. I did that overnight and my phosphates increased quickly but nitrate didn't. It may be different in your tank though.

[rovster]

Only problem with the 0 nitrates is that sometimes phosphate becomes a problem. Whenever my nitrates bottom out I notice an increase in both cyano and phosphate. I dose sodium nitrate and within a few days phosphate goes down and cyano getts better. I also run Siporax and carbon dose. I try to keep nitrates barely readable. Once the salifert kit is clear, in goes nitrate. I don't even use GFO any more. I dose nitrate to help phosphate, weird I know, LOL!

[amcvay1979]

Only problem with the 0 nitrates is that sometimes phosphate becomes a problem. Whenever my nitrates bottom out I notice an increase in both cyano and phosphate. I dose sodium nitrate and within a few days phosphate goes down and cyano getts better. I also run Siporax and carbon dose. I try to keep nitrates barely readable. Once the salifert kit is clear, in goes nitrate. I don't even use GFO any more. I dose nitrate to help phosphate, weird I know, LOL!

I do the same thing. When my Phosphates go up I add Nitrate and then both go to zero.

[bertoni]

The nitrate will feed microbes that consume mineralized nutrients (like phosphate and the nitrate). The microbes then seem to convert the nutrients into a skimmable form, as far as we can tell. So dosing nitrate to reduce phosphate makes sense, although I'd be cautious about it. It seems generally safe, though.

[tmz]

Sometimes. undetecable nitrate is ok; sometimes it may indicate a nitrogen deficiency.

Organisms do need nitrogen along with phosphorous to grow. So, one or the other can be limiting and dosing some nitrogen( nitrate ammino acids, ammonium etc) may increase PO4 uptake However, there may be undetecable nitrate and adequate nitrogen in some cases from traces of ammonium, nitrite etc.

[rovster]

Sometimes. undetecable nitrate is ok; sometimes it may indicate a nitrogen deficiency.

Organisms do need nitrogen along with phosphorous to grow. So, one or the other can be limiting and dosing some nitrogen( nitrate ammino acids, ammonium etc) may increase PO4 uptake However, there may be undetecable nitrate and adequate nitrogen in some cases from traces of ammonium, nitrite etc.


Good point. That said, it seems just as a general observation that these nitrate deficient tanks all seem to be carbon dosing. Not sure if there is any concrete evidence, but its something that I've seen as a general thread that runs through all these threads.

[Art13]

i'm trying this out as well, as i'm having an issue with cyano and bryopsis. usually i just run a gfo reactor, i think the batch of gfo i got was bad though as i'm still reading phosphates after the reactor. I have the potassium nitrate laying around so i'm doing this instead. I have seen po4 drop fast after i dose nitrates, but i've never been consistent with it, so i'm going to give it a go and see how it works out.

[amcvay1979]

carbon dosing can be a fickle beast. While we're trying for zero nitrate and phosphate you'll soon learn that corals don't grow in those environments so you're walking that bleeding edge of dosing enough carbon to get phosphate low (.02-.08 ppm) and Nitrate detectable (.25-.75 ppm) and soon enough you'll have something die and one or both will spike, you'll leave for a long weekend and not feed enough and both will fall to zero. You'll overfeed and spike phosphates and they won't go down for a week until you dose nitrates...it's all part of the dance I suppose.

[scar79]

I just wanted to bump this thread with a follow-up. After my initial dose in the OP, I dosed one more time as nitrate started to drop out. I didn't notice much of anything other than increased algae growth, so I laid off. Of note, the tank had just recovered from an STN event a few weeks prior. My guess is things hadn't settled down yet.

Fast forward to mid September. I dosed KNO3 again when I noticed my phosphates starting to climb. My pale/brown SPS showed improved greens within 24 hours. I've been dosing weekly trying to maintain about .5 ppm and my greens have literally never been so vibrant. I'm seeing better polyp extension from all SPS and my birdsnest is really starting to take off. I am going to gradually increase lighting intensity in hopes that my now properly supplied corals can really start to grow out.

My algae growth is definitely up a bit, but it's worth it. My current filtration is my skimmer and 1L of marine-pure spheres. No other mech filtration, no phosphate removers, no carbon. I am adding carbon tonight to see if there's a reduction in dust algae growth on the glass, but regardless, I'll deal with that for the colors I'm seeing.

[bertoni]

That's interesting. I wonder whether the phosphate was causing the browning directly by encouraging zooxanthellae growth. That's the most obvious possibility, but who knows. In any case, it's good to hear reports about the effects of nitrate dosing.

[tmc1313]

I just want to add my experience nitrate dosing. I have been dosing KNO3 for roughly 3 months now. I add 25ml every other day of a 60g/L solution I made up using "stump remover". This keeps my nitrates at around 2.5 ppm. My phosphates run at around .02-.04. I resorted to this method because I continually have had O nitrates using the salifert test kit and had trouble with pale coral color. I don't keep a heavy bio load of fish and pretty much feed a high quality flake food exclusively. They will get a frozen treat once in a while, but very rarely. I had stopped doing water changes, tried amino acids and coral food, but nothing seemed to work until I tried KNO3. I notice a difference literally within a week of dosing. My next step is to check K levels using AA or ICP. I will check back after I have tested those numbers as I'm curious to what they may be. If they are high, my corals sure don't show any sign of being unhappy at the moment. I've only done two 3 gallon water changes in the 3 months I've been dosing. My aquarium is 120 gallons. I will post the most recent pic I have of the tank taken roughly two weeks ago so you can see my results thus far. Granted, I'm not keeping the latest trendy acros or the hardest to keep, but I'm happy with what I have and the color and growth seems to be on the right track.
https://s19.postimg.org/wvfxspfj7/20160929_201126.jpg (https://postimage.org)photo sharing websites (https://postimage.org/)

[orly20]

I just want to add my experience nitrate dosing. I have been dosing KNO3 for roughly 3 months now. I add 25ml every other day of a 60g/L solution I made up using "stump remover". This keeps my nitrates at around 2.5 ppm. My phosphates run at around .02-.04. I resorted to this method because I continually have had O nitrates using the salifert test kit and had trouble with pale coral color. I don't keep a heavy bio load of fish and pretty much feed a high quality flake food exclusively. They will get a frozen treat once in a while, but very rarely. I had stopped doing water changes, tried amino acids and coral food, but nothing seemed to work until I tried KNO3. I notice a difference literally within a week of dosing. My next step is to check K levels using AA or ICP. I will check back after I have tested those numbers as I'm curious to what they may be. If they are high, my corals sure don't show any sign of being unhappy at the moment. I've only done two 3 gallon water changes in the 3 months I've been dosing. My aquarium is 120 gallons. I will post the most recent pic I have of the tank taken roughly two weeks ago so you can see my results thus far. Granted, I'm not keeping the latest trendy acros or the hardest to keep, but I'm happy with what I have and the color and growth seems to be on the right track.
https://s19.postimg.org/wvfxspfj7/20160929_201126.jpg (https://postimage.org)photo sharing websites (https://postimage.org/)

Hi Todd
I know it's an old one but could you fill me in on your icp K results and what did you finally do? Thansk

[cliffhanger]

Sometimes. undetecable nitrate is ok; sometimes it may indicate a nitrogen deficiency.

Organisms do need nitrogen along with phosphorous to grow. So, one or the other can be limiting and dosing some nitrogen( nitrate ammino acids, ammonium etc) may increase PO4 uptake However, there may be undetecable nitrate and adequate nitrogen in some cases from traces of ammonium, nitrite etc.

if I have a nitrogen deficiency in my case, when I measure zero nitrate, how can I fix it without adding kno3 and that phosphate does not rise to the clouds

[bertoni]

There are some sodium nitrate products available if you don't want to use potassium nitrate. Neither of those will raise phosphate, though.

[cliffhanger]

There are some sodium nitrate products available if you don't want to use potassium nitrate. Neither of those will raise phosphate, though.

There is a way without adding any chemical, currently I have a biological load in high fish but I can not raise the nitrate by feeding more without increasing the phosphate

[bertoni]

Amino acids won't contain any phosphate, but they do have fixed nitrogen.

[coralcruze2020]

might add that I use stump remover to dose No3 to my tank. there is a thread somewhere about it. been doing so for years without any ill effects. PM me if you need more info.