Nitrates and Phosphates

anthonys_aqua

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#1
Idk if this has ever been discussed before, Im sure it has.

Always wonder what exactly contributes to nitrate and phosphates, like does flakes add more nitrates than phosphates etc.

Does fish poop add more nitrates than phosphates etc.

My tank always seem to get a lot more phosphates than nitrates.
 

Jimbo327

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#2
I think it all depends on the food. Some food have higher phosphates such as reef roids.

As far as nitrates vs. phosphates, usually it is much easier to lower nitrates. When you carbon dose, it drop nitrates a lot more than phosphates.

Phosphates can bind to your rocks and substrate. When you do water change by 50%...then you will lower nitrates by 50%. However, the phosphates will not drop 50%...the phosphates will leach back out of the rock/sand in the water.

That is the reason why your phosphates are generally higher than nitrates.
 
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drexel

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#3
Usually flakes and pellets will contain higher amounts of phosphates and frozen will have less. I contribute high nitrates to poor biological filtration and/or poor skimming. For me, if you have a measure of NO3, then you have enough. But if you measure zero, then you are nitrogen limited and may benefit from ammonium (bicarbonate) dosing or feeding more frequent smaller meals throughout the day. Nutrient levels also depends on biomass, so if you have more fish than corals (in biomass) then most likely you will have higher nutrients, unless your export game is on target. There are no magic ratios with nutrients, absolutely none, zero, nada, zilch. Anyone who tells you otherwise doesn't have a clue on how it works. And if anyone mentions Redfield ratio, just smack them (kidding of course) and tell them to read a book.
In regards to phosphates, there are many types of phosphates, so the topic can be confusing to some. I think RHF wrote a really article of phosphates that explains it. Martin Moe, Sprung and Delbeek have also written about phosphates in their many books (that most, if not all reefers should read).
 
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#4
This is a question that seems to come up every other month or so. I am not an expert but I will share what I have learned based on my own homework and I hope this can help, as it is a challenge that all reef keepers must learn to control for long term success. I myself have struggled with this balance as well and found many very short answers with anecdotal cures that didn't help me in the long run.

To put it simply, phosphates are directly linked to the food. Where nitrates are linked to to anything that releases ammonia like decaying fish food, dead animals, fish poop, and uriune. Nitrates are end result of the ammonia/nitrogen cycle.

Dried foods are naturally higher in phosphates since they are essentially concentrated natural/whole foods. Every living thing shrimp/algae/fish/humans/grass/trees is made up at the molecular level of phosphorous, it is what binds DNA strands together and creates the cell walls of every living cell. So if you dry out and concentrate those living things (IE make pellets or flakes) you will produce a food that is naturally higher in phosphates. This is why frozen foods are generally lower in phosphates and dried food are usually higher in phosphates. Frozen food just isn't as concentrated and generally contains less fillers. Fillers like wheat, potato starch, dried gluten meal...yeah really this stuff is in dried fish foods. I am sure my wrasse really needs that potato starch in his diet. I look at pellet and flake foods as something quick and easy to feed when I am in a rush or something to put in an autofeeder when I am out of town. They are essentially the hot dog and potato chips of fish feeding. I actually enjoy feeding my fish fresh and frozen foods since it is an interaction that I get to have with them. I spent a lot of money on those little guys I don't want them to hide all of the time. All of my fish now recognize me as the feeder and when I move around the living room they follow me around. When I sit and watch TV they stare at me. When I walk through the front door they come out to greet me.

Another common source for both nitrates and phosphates is tap water. So exhausted or worn out RODI filters can also be an issue. One more phosphate source that is often overlooked and easily avoided is low grade activated carbon. Some cheaper activated carbons use phosphates in the manufacturing process so they can actually release phosphates into the system. This is more common in peletized carbon so just do your homework or stick to a brand that is specifically made for reef aquariums.

Like Jimbo said before the challenge in phosphate reduction is that the phosphates bind to our substrates like rock, sand, filter socks, sponges and bio media like bio plates and cubes. The phosphate will essentially maintain an equilibrium between the substrate and the water column. The only way to get the phosphates out of the substrate is to have the phosphates in the water column low enough for long enough for the substrate to release them essentially finding a lower equilibrium. For this you will need a filtration media specifically designed to remove phosphates fro the water like GFO or aluminum sulphate, or start dosing Lantham Chloride(LC). If you want to start dosing LC do your homework as it can crash/poison your tank if not done properly. I think Jimbo has some experience with this method so he may be able to give you some pointers. You can also set up a macro algae refugium or algae reactor to remove phosphate but just keep in mind that this will also reduce nitrates and usually faster than it will drop phosphate.

I don't have as much info for nitrates as they are just not as complex of a subject. As stated earlier nitrates are the end result of the ammonia/nitrification cycle. Anything that releases ammonia will raise nitrates. So in my head I just sort of consider the two as the same thing with nitrates just being detoxified ammonia. As long as you have a sufficiently sized biofilter ammonia shouldn't be an issue after your biofilter has matured. During the first 6mo. or so ammonia can still be an issue and should be monitored. After that I have found that dead things and over feeding just cause crazy rapid nitrate spikes. I actually have an aquaintence who doses ammonia to keep his nitrate levels up, this is a discussion for another time though. Nitrates can be removed in many ways like water changes, carbon dosing, refugiums, algae turf scrubbers, algea reactors, sulpher denitrators, etc. The most effective way IMO is through the use of a macroalgae refugium. Just need a light and chamber to grow algae in.

Water changes can reduce nitrates and phosphates to some degree but are fairly ineffective at correcting levels once they raise to problem levels. The reason for this being that when doing a water change you are generally just changing 10%-20% of the water at a time. So if you have 30ppm of nitrate and .30 phosphate and do a 10% water change you have only dropped the levels to 28ppm nitrate and .28ppm phosphate. When you consider these numbers it becomes clear that something more must be done and water changes alone are not a good long term management strategy for these nutrient pollutants.

The main thing that I have learned about controlling both nitrates and phosphates is that it is a balance between import and export. What you import through food and supplements needs to have an equal removal source otherwise the numbers will rise. If your export means are too effective the numbers can bottom out and cause issues like dino bloom or coral bleaching. The best way to handle both of these nutrients/pollutants is to never let them get out of check in the first place.

Sorry for such a wordy answer. I just find that the subject of nutrient pollution comes up frequently and many new comers look for just a simple answer. The answer is just that a simple one doesn't really exist and it is a balance that really needs to be understood for success in the hobby.

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anthonys_aqua

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#6
This is a question that seems to come up every other month or so. I am not an expert but I will share what I have learned based on my own homework and I hope this can help, as it is a challenge that all reef keepers must learn to control for long term success. I myself have struggled with this balance as well and found many very short answers with anecdotal cures that didn't help me in the long run.

To put it simply, phosphates are directly linked to the food. Where nitrates are linked to to anything that releases ammonia like decaying fish food, dead animals, fish poop, and uriune. Nitrates are end result of the ammonia/nitrogen cycle.

Dried foods are naturally higher in phosphates since they are essentially concentrated natural/whole foods. Every living thing shrimp/algae/fish/humans/grass/trees is made up at the molecular level of phosphorous, it is what binds DNA strands together and creates the cell walls of every living cell. So if you dry out and concentrate those living things (IE make pellets or flakes) you will produce a food that is naturally higher in phosphates. This is why frozen foods are generally lower in phosphates and dried food are usually higher in phosphates. Frozen food just isn't as concentrated and generally contains less fillers. Fillers like wheat, potato starch, dried gluten meal...yeah really this stuff is in dried fish foods. I am sure my wrasse really needs that potato starch in his diet. I look at pellet and flake foods as something quick and easy to feed when I am in a rush or something to put in an autofeeder when I am out of town. They are essentially the hot dog and potato chips of fish feeding. I actually enjoy feeding my fish fresh and frozen foods since it is an interaction that I get to have with them. I spent a lot of money on those little guys I don't want them to hide all of the time. All of my fish now recognize me as the feeder and when I move around the living room they follow me around. When I sit and watch TV they stare at me. When I walk through the front door they come out to greet me.

Another common source for both nitrates and phosphates is tap water. So exhausted or worn out RODI filters can also be an issue. One more phosphate source that is often overlooked and easily avoided is low grade activated carbon. Some cheaper activated carbons use phosphates in the manufacturing process so they can actually release phosphates into the system. This is more common in peletized carbon so just do your homework or stick to a brand that is specifically made for reef aquariums.

Like Jimbo said before the challenge in phosphate reduction is that the phosphates bind to our substrates like rock, sand, filter socks, sponges and bio media like bio plates and cubes. The phosphate will essentially maintain an equilibrium between the substrate and the water column. The only way to get the phosphates out of the substrate is to have the phosphates in the water column low enough for long enough for the substrate to release them essentially finding a lower equilibrium. For this you will need a filtration media specifically designed to remove phosphates fro the water like GFO or aluminum sulphate, or start dosing Lantham Chloride(LC). If you want to start dosing LC do your homework as it can crash/poison your tank if not done properly. I think Jimbo has some experience with this method so he may be able to give you some pointers. You can also set up a macro algae refugium or algae reactor to remove phosphate but just keep in mind that this will also reduce nitrates and usually faster than it will drop phosphate.

I don't have as much info for nitrates as they are just not as complex of a subject. As stated earlier nitrates are the end result of the ammonia/nitrification cycle. Anything that releases ammonia will raise nitrates. So in my head I just sort of consider the two as the same thing with nitrates just being detoxified ammonia. As long as you have a sufficiently sized biofilter ammonia shouldn't be an issue after your biofilter has matured. During the first 6mo. or so ammonia can still be an issue and should be monitored. After that I have found that dead things and over feeding just cause crazy rapid nitrate spikes. I actually have an aquaintence who doses ammonia to keep his nitrate levels up, this is a discussion for another time though. Nitrates can be removed in many ways like water changes, carbon dosing, refugiums, algae turf scrubbers, algea reactors, sulpher denitrators, etc. The most effective way IMO is through the use of a macroalgae refugium. Just need a light and chamber to grow algae in.

Water changes can reduce nitrates and phosphates to some degree but are fairly ineffective at correcting levels once they raise to problem levels. The reason for this being that when doing a water change you are generally just changing 10%-20% of the water at a time. So if you have 30ppm of nitrate and .30 phosphate and do a 10% water change you have only dropped the levels to 28ppm nitrate and .28ppm phosphate. When you consider these numbers it becomes clear that something more must be done and water changes alone are not a good long term management strategy for these nutrient pollutants.

The main thing that I have learned about controlling both nitrates and phosphates is that it is a balance between import and export. What you import through food and supplements needs to have an equal removal source otherwise the numbers will rise. If your export means are too effective the numbers can bottom out and cause issues like dino bloom or coral bleaching. The best way to handle both of these nutrients/pollutants is to never let them get out of check in the first place.

Sorry for such a wordy answer. I just find that the subject of nutrient pollution comes up frequently and many new comers look for just a simple answer. The answer is just that a simple one doesn't really exist and it is a balance that really needs to be understood for success in the hobby.

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Makes sense

I’ve never really had issues with nitrates as they almost bottomed out the other day.

I think the refugium and skimmer takes care of nitrates for the most part.

My phosphate always rises though and I would say 50% of the rocks in my tank are only about 15 months old and they’re just releasing it back into the water but also probably wasn’t smart of me to add reef roids into the auto feeder, a large amount at that.

So for now I’ll keep changing the gfo even though it’s a pain lol
Takes forever to rinse clear and always falls out of the media reactor which I hope isn’t a big deal


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bakbay

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#8
I use LC to drop phosphates.
What? You’re not afraid of those Hawaiian YTs dying due to LC? :)

I’ve use PhosphateRx for more than 7 years across several different tanks and all my YTs and other fish have been fine. If they end of having issues, it might be purely a coincidence.
 

drexel

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#9
Nitrate is simple and easy to figure out the source, as stated above, it’s the end (it’s near the end) of the nitrogen cycle. In a well established tank with a robust bio filter, it will be converted to nitrogen gas, that’s why some tanks run near zero. Phosphate or I should say phosphorus comes in 3 forms, dissolved inorganic phosphate (orthophosphate and phosphate), dissolved organic phosphate and particulate organic phosphate. Dissolved inorganic phosphate can be removed by a skimmer as it attaches to the air bubbles, but that leaves a lot of leftover phosphate in other forms, bacteria, algae, detritus, etc
Phosphorus is a building block, so it will bind or absorb into coral skeletons, so it’s introduced again with certain media in calcium reactors (reborn).
RHF wrote a great article on the subject here: https://reefkeeping.com/issues/2006-09/rhf/index.php


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drexel

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#10
Nitrate is simple and easy to figure out the source, as stated above, it’s the end (it’s near the end) of the nitrogen cycle. In a well established tank with a robust bio filter, it will be converted to nitrogen gas, that’s why some tanks run near zero. Phosphate or I should say phosphorus comes in 3 forms, dissolved inorganic phosphate (orthophosphate and phosphate), dissolved organic phosphate and particulate organic phosphate. Dissolved inorganic phosphate can be removed by a skimmer as it attaches to the air bubbles, but that leaves a lot of leftover phosphate in other forms, bacteria, algae, detritus, etc
Phosphorus is a building block, so it will bind or absorb into coral skeletons, so it’s introduced again with certain media in calcium reactors (reborn).
RHF wrote a great article on the subject here: https://reefkeeping.com/issues/2006-09/rhf/index.php


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rishma

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#10
For the first time ever I am able to consistently manage phosphate and nitrate level with carbon dosing. In the past I had had to manage phosphates separate from nitrate or the carbon dosing would drive nitrate to zero. Using TM NP bacto balance and carefully managing food input has kept both steady and in range for over a year now. I actually had to dose phosphates this week after a couple of days of feeding were missed.
 
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