Nitrate Dosing

[lionfish5740]

Keep us updated on the nitrite dosing! Sometimes the best inventions are just luck.

Follow up for the nitrite dosing: I never found any issues with fish or corals but I lost my peppermint shrimp shortly after posting before. Wasn't too distraught because the shrimp was turning into a nightmare by pulling on zoa skirts and also SPS polyps :mad2: Regaurdless, I halted the dosing for the time being to be on the safe side. My snails also died so they must be pretty sensitive also.

I've now set up a new tank and everything is doing great so I thought that I would try dosing nitrite again. Seen an almost immediate result that I didn't notice in the old tank, masses of amphipods came out of the rocks. Didn't realize for a while but they were all dying and my skunk cleaner almost died also. Couple emergency water changes saved him but hundreds of amphipods died. Don't think that I'll do that again. Bought some tech grade sodium nitrate for hydroponics this time and it's too early to give any feedback on how it's going.

Not sure why I didn't notice the same in the old tank, maybe they were all eaten, it was only 8 gallons. I'm still curious what the effects are with other critters in the tank like bristle worms but that will have to be done in a beaker or the 1/2 gallon tank that I have. I've only seen one bristle worm in my tank and it's in the sump so it's safe from experimentation. It appears that my hermit crabs were lethargic for a few days but none died.

 

[Randy Holmes-Farley]

What grade of nitrite were you dosing?

How much were you dosing?

 

[sureal00]

phosphate rx is pretty good in removing phosphate

 

[tonizzy22]

Using amino acids will feed corals and then turn into nitrates without adding to phosphate levels. It works so well I had to stop gfo and dose phosphates to balance it out.

 

[Vucious]

Do people actually use phosphate Rx on a regular basis? I thought it was only used to bring very high level of phosphate down and then use GFO to maintain.

 

[Lazys Coral House]

I always thought 0 nitrates were ideal. Most places I read in the past stated for a coral reef tank undetectable Nitrates where best. Especially for SPS corals.

Achieving that has never been a problem. I have always had smaller fish, fed light and had decent skimmer. I thought that was the right thing to do and good for the coral.

For many years my corals were pale and just not as colorful as I would see them in other tanks. It was disappointing consider how much time I invested in the system and how much work I put into making it stable.

About 3 months ago after conversations with a few hobbyists on my local forum I decided to try raising the nitrate to a detectable level to see if that would influence coral color.

I first started by doubling up on feedings. After a couple weeks there was no change in corals or nitrate level.
A friend recommend buying more fish and feeding even more. I picked up a Powder Blue and Moorish Idol. Once they got out of quarantine both fish where quite skinny and malnourished. I had flat packs and cube trays of frozen foods from Brine Shimp. Thought why not make my own food. Food that would be good for all the fish, inverts and coral. That is what I did, it included Mysis, Krill, Rotifers, Copepods, LOTS of Nori, Brine Shrimp, Reef Chili and other fine Powder Foods.

I feed heavy with the new mix for a few weeks. Noticed my cheato started growing and a bit of hair algae started showing up in the overflow and other areas not reachable by the tangs. Although feeding quite a bit it probably wasn't what others would consider a lot. About 3 – 4 cubes a day in total. (300g total system size) Still no improvement in coral color and no nitrates showing yet. I knew they had to eventually show up but I was worried putting all this food in the system…. It can’t be good for it?

I went on the search for liquid Nitrates. Brightwell sells it although it wasn't readily available, I was able to locate a vendor with the help of Brightwell. The magic juice arrived and I dosed enough to raise the nitrates to 2. The next day after work I noticed my Red Dragon Acro that always looked like a Pink Dragon seemed to have a bit darker color to it. I thought it wasn't possible after 24 hours and blew it off. Two days later it was back to its normal pink color. I checked nitrates and they were back to 0. I didn't know the system would consume Nitrates.

I dosed again. Same amount but this time I decided to test and dose daily to see if it would continue to consume them. I was surprised to find the system consumed .25 - .5 Nitrates per day. The dosing needed to be done daily. I continued to do it daily and was quite surprised to see the color in many corals improving. After about two weeks I decided to raise the Nitrate level up to 5. That is when the color of corals changed quite dramatically. The Red Dragon was as Red as I had seen in any other picture or tank. After about two weeks of this I was almost out of the Nitrate solution and it wasn't cheap.

I didn't want to dose forever and incur another expense so I took the feedings to a whole new level. 6 – 10 cubes of homemade food a day + flakes and pellet mix when I am in the room. I have continued to do this for the past month. The fish are looking healthy and very pleased with the transformation of color with many of the corals. If I am lax for a couple days I can see changes in the red dragon. It is the canary relative to nutrients in the tank. I have also noticed a sudden surge in growth of many corals.
I know at some point I will likely have to reduce feedings but will continue to target higher nitrates as I am sold it is a key contributor to maintain the darker deeper coral colors.

Negative Effects. I haven’t had the system running higher nutrient for all that long so I don’t know if there will be negative effects other than having to clean glass more often or have more algae to deal with.

Other Positive Effects: Prior to running detectable Nitrates in the system I struggled with keeping Phosphate in check. I always had to run GFO or they would creep up on me. Since running higher nitrates I have been able to take the GFO reactor offline. Sounds silly doesn’t it. Raise Nitrates and Phosphates go down. I am sure Randy could speak to this but guessing Nitrates and Phosphate consumption is linked. Similar to a coral needing Alk, Ca and Mag ion’s to build its coral Skelton. If one is considerably low it can’t bind them together or something scientific like that.

I don’t know what the sweet spot is with Nitrates but it definitely isn’t zero!

 

[Vucious]

This was my goal when I started this thread. I wanted to see if anyone had success with dosing nitrate which not only make corals a little happier but also reduce phosphate without using GFO. Keep us updated lazyliving!

 

[Keithcorals]

This is too funny I've done this for years and had people tell me I was nuts. I have dosed nitrate to reduce phosphate and phosphate to reduce nitrates. It seems if they get out of balance you end up with a lot of one or the other. I currently dose both to keep my nutrient levels detectable. I'm using Seachem flourish nitrogen and Seachem flourish phosphorus. So I put plant food in my tank and don't have algae problems or use GFO or other Products to control my nutrients just plant food a skimmer and a refugium

 

[Keithcorals]

Someone should make reef fertilizers I'd buy them

 

[UK_Pete]

Actually its an interesting question what the difference between adding food and adding nitrate / phosphate is if the aim is to raise nitrate and phosphate. Wonder if Randy is still checking this thread. Did a small amount of reading and it looks like very roughly 10 times more carbon is added than any other nutrient apart from calcium in skimmate, which might be reasonably similar to food, so if someone was adding 4 cubes a day, that must be quite a lot of carbon. What form is this carbon in and what happens to it? Does it act the same as vodka / vinegar / sugar, creating biological oxygen demand and feeding bacteria? So is heavy feeding just the same as carbon dosing? I've been feeding more heavily to try to raise nitrates and phosphates too but I wonder if direct nitrate / phosphate dosing would be better.

 

[Randy Holmes-Farley]

The organics in food act similarly to vinegar or vodka in the they are metabolized, BUT they already carry as much nitrogen and phosphate as a typical bacteria might incorporate, so simple dosing of food cannot bring down nutrients by driving bacterial growth since it brings in as much as the bacteria may take out (and, of course, there is a lot of metabolism that doesn't end up exporting nutrients, such as a fish excreting N and P but little organic carbon, so nutrients will rise with increased feeding).

The organics in foods and otherwise produced in the tank are why a deep sand bed or live rock can reduce nitrate: bacteria in the low O2 regions use nitrate to metabolize these organics just as they would vodka or vinegar.

 

[Randy Holmes-Farley]

This is too funny I've done this for years and had people tell me I was nuts. I have dosed nitrate to reduce phosphate and phosphate to reduce nitrates. It seems if they get out of balance you end up with a lot of one or the other. I currently dose both to keep my nutrient levels detectable. I'm using Seachem flourish nitrogen and Seachem flourish phosphorus. So I put plant food in my tank and don't have algae problems or use GFO or other Products to control my nutrients just plant food a skimmer and a refugium

That's why I use multiple methods, some imbalanced one way and soem the other. So there is never a time when my system cannot export N and P for lack of the other.

I use GFO to imbalance toward phosphate removal, organic carbon dosing along with lots of live rock to imbalance toward nitrate removal, and macroalgae to be a balanced removal.

 

[Randy Holmes-Farley]

I always thought 0 nitrates were ideal. Most places I read in the past stated for a coral reef tank undetectable Nitrates where best. Especially for SPS corals.

FWIW, zero nitrate and undetectable nitrate are very different things. The natural nitrate level in the near surface regions of the ocean are often 0.1 ppm or less. THat is a level that you couldn't reliably detect with most test kits, but is very different than zero.

So if you cannot detect nitrate, you may still have natural levels, or may have well below natural levels, and the effects on corals may be different.

My revised article "Nitrate and the Reef Aquarium" will come out about Feb 1. Here's the section on nitrate in the ocean:


Nitrate in the Ocean
Nitrogen takes many forms in the ocean, one of which is nitrate.¹ Other forms include dinitrogen (N₂), ammonia (NH₃/NH₄⁺), nitrite (NO₂^-), and a myriad of nitrogen-containing organic compounds. Of the inorganic species, nitrate is often, but not always, the highest in concentration. Concentrations in the ocean vary considerably from location to location, and also with depth.² Surface waters are much lower in concentration due to scavenging by various organisms, and are often less than 0.1 ppm nitrate (note that all concentrations in this article are in ppm nitrate ion, and not in ppm nitrate nitrogen). Deeper ocean waters typically range from 0.5 to 2.5 ppm nitrate. Surface regions where upwelling of deeper water takes place will also have these higher values.

Most of the nitrate present in the ocean results from the recycling of organic materials. The degradation of plankton, for example, provides nitrate. This can be shown in a simplified chemical equation describing what happens when organic “food” is digested with oxygen:

(CH₂O)₁₀₆(NH₃)₁₆(H₃PO₄) + 138 O₂ → 106 CO₂ + 122 H₂O + 19 H⁺ + PO₄^3- + 16 NO₃^-

which in words reads as:

plankton + oxygen → carbon dioxide + water + hydrogen ion + phosphate + nitrate

Note that this process consumes alkalinity (the H⁺ being produced shows this). So when nitrate is accumulating in a reef tank, alkalinity is being depleted. Production of 10 ppm of nitrate will deplete about 0.16 meq/L (0.45 dKH) of alkalinity. If this nitrate is removed by water change, that alkalinity is lost forever. If the nitrate is taken up by an organism (algae, coral, bacteria, etc.) and used, then all of that alkalinity is returned to the system (see equations below showing this fact).

Other sources of nitrogen to the ocean are volcanic emissions (mostly as ammonia), fixing of N₂ by blue-green algae (also known as cyanobacteria), and run-off from land. All of these become part of the nitrogen cycle, and a portion will end up as nitrate.

 

[UK_Pete]

So food which is used for energy (in fish etc) will contribute N and P to the water, but food which is used to build fish weight up will take N, P and carbon in about the same proportion as the food I guess? Uneaten food will only take oxygen out of the tank in its net effect, and dosed N and P in salt forms will take carbon out of the aquarium (and oxygen)?

BTW you said that you dose organic carbon to remove nitrate, but I thought this mechanism also needed phosphate to work. But you also use GFO which must take some phosphate out, it seems something is unbalanced there. Does that mean that your food probably contains more phosphate than your skimmate (assuming the end result of your carbon dosing is to make something which is skimmed out)? Or does your tank use the nitrate reduction method where nitrate is the energy source (but I thought carbon was not required for that one)?

Thanks, Pete

 

[Randy Holmes-Farley]

So food which is used for energy (in fish etc) will contribute N and P to the water, but food which is used to build fish weight up will take N, P and carbon in about the same proportion as the food I guess? Uneaten food will only take oxygen out of the tank in its net effect, and dosed N and P in salt forms will take carbon out of the aquarium (and oxygen)?

Yes to all, except that the carbon taken out may just be from carbon dioxide if it is a photosynthetic organism that is using it.

 

[Randy Holmes-Farley]

BTW you said that you dose organic carbon to remove nitrate, but I thought this mechanism also needed phosphate to work. But you also use GFO which must take some phosphate out, it seems something is unbalanced there. Does that mean that your food probably contains more phosphate than your skimmate (assuming the end result of your carbon dosing is to make something which is skimmed out)? Or does your tank use the nitrate reduction method where nitrate is the energy source (but I thought carbon was not required for that one)?

Thanks, Pete

It definitely also takes out phosphate too, but is imbalanced toward nitrate because bacteria growing in low O2 regions use nitrate both as a source of oxygen (wasting the N in the nitrate, producing N2) and also as a source of N for body tissues.

The GFO would ideally take up the left over phosphate.

Here's a blurb on organic carbon dosing from an upcoming nitrate article:

Organic carbon dosing involves adding a soluble organic compound to the aquarium which spurs bacterial growth. Typical organics used can be ethanol (as vodka), acetic acid (as vinegar), calcium acetate (as lime saturated vinegar), sugar (sucrose) and many others. Vodka and vinegar are by far the most popular. I use vinegar.

These organic molecules can be used by many organisms, including corals, but the main intent is to drive bacterial growth. To grow, the bacteria need a source of nitrogen and a source of phosphate, and a large portion of these they remove directly from the water. The bacteria may grow out of sight (inside live rock or sand, in refugia, in tubing, etc.). They may also grow in globs in the display tank. They have to grow somewhere. If they become unsightly, try dosing a different organic that may drive a different set of species that may grow in a different location. I’ve had them often seem to grow on GAC (granular activated carbon media) in a canister filter I previously used, allowing relatively easy export by rinsing the GAC once every couple of weeks.

I’ve never heard any plausible argument why dosing multiple organics at once is desirable, but many people do it and there is likely no harm in doing so. The idea that multiple organics drive a diversity of bacterial species is just speculation, and even if true, I don’t see the benefit.

The bacteria themselves can then be skimmed out, or used as a food for filter feeders, or both (most people probably have both to some extent, unless they do not use a skimmer). The bacteria may grow partly in low O₂ regions (such as in sand or rock) and partly in highly oxygenated environments. Since metabolism in low O₂ regions uses relatively more nitrate than phosphate compared to metabolism in a high O₂ environment, the relative amounts of nitrate and phosphate reduction an aquarists observes may vary from system to system.

Nitrate is always reduced to a greater extent than phosphate simply because bacteria need a lot more nitrogen than phosphorus, but metabolism of organics in low O₂ regions may skew it even more, and sometimes can leave the aquarium with little nitrate and an excess of phosphate that they bacteria don’t “want”. In such a case, a phosphate binder might usefully export this remaining phosphate. Alternatively, some aquarists have dosed nitrate directly to the aquarium to allow the residual phosphate to be consumed.
These linked articles describe vinegar and vodka dosing in more detail.

One potential drawback that may have played a role in some tank problems is that the bacteria that thrive when organic molecules are dosed may be benign (and appear to be in almost all cases), but might actually be pathogenic in others. That is, the added organics may enhance bacterial infections if those bacteria causing the infection (of fish, corals, etc.) are able to take up the added organics and use them to grow faster. I think this risk is low, but it may be real. If you have unexplained problems that might fit this description, and are organic carbon dosing, try not dosing for an extended period.

A second potential drawback of organic carbon dosing is the potential for proliferation of unsightly cyanobacteria in the display tank. There are many species of cyanobacteria, and some can consume the organics we add in this method. If they become a primary consumer, then something may need to be done, such as switching to a different organic compound to dose, or reducing phosphate with a binder such as GFO (granular ferric oxide).

 

[tonizzy22]

Someone should make reef fertilizers I'd buy them

Brightwell aquatics makes neonitrate and neophos for reef tanks.

 

[Keithcorals]

Brightwell aquatics makes neonitrate and neophos for reef tanks.

Thanks I do t know how I didn't know about them. I just ordered both.

 

[UK_Pete]

Very interesting to see how these processes relate to each other in tanks. I guess then that the coral paste food stuff that I have been adding, expecting it to increase N and P, will have been adding a balanced amount of carbon and the net effect is not an increased level of N and P but an increased bacterial population, and in addition that makes the possibility of trace element imbalance arise (if the food trace element content is different to the skimmate trace element content).

What do you think about dosing of aminos for corals? I believe the zeo people use this to provide N and P to corals in ULNS, I guess the idea is that bacteria won't use up the N and P in amino’s, making them stay in the water for longer so the corals can take the nutrients up, but do you believe that bacteria won't immediately break these aminos down regardless?

And do you think amino’s or free organic carbon are beneficial for SPS corals? Reading one of your articles today on organics I see that natural surface waters (not sure if that includes reefs) have around 150 ppb carbs, 10 ppb amino’s, 150 ppb humic compounds - those figures all sound really low (IE I dose about 2.5 ppm ethanol per day). I'm beginning to wonder about how good DOM is for SPS, what with the information around about bacterial infections causing RTN, and I wonder if all this DOM just feeds it.

Might there be an alternative approach for SPS only tanks where N and P are dosed as salts, or removed with GFO and sulphur nitrate reactors if required, and carbon is kept as low as possible, and would this more closely replicate natural reefs?

Hope thats not too many points for one post Randy!

Cheers, Pete

 

[rayn]

You all are making me want to go test my tanks! This just goes to show the difference in tanks across the board. Heck across the room even. I have tanks that are at that 0 nitrate level and others that I am still fighting with. Never thought about dosing nitrate to help bring the PO4 down though.