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Plants require 17 nutrients to grow (assuming the light is of sufficient intensity for the plant species, and the correct spectrum). Macros are oxygen, phosphorus, potassium, sulphur, calcium, hydrogen, carbon, magnesium and nitrogen. Micros are boron, iron, chloride, nickel, copper, manganese, zinc and molybdnum. If some of these, especially some of the micronutrients, are in excess, plants can shut down assimilation of certain other nutrients, creating an insufficiency. This is why the nutrients need some form of being in proportion, which is why not all fertilizers are advisable. And why dosing any single nutrient can be more harm than good.

Phosphorus will be more than sufficient from fish foods, assuming a normally-stocked aquarium using a natural or low-tech method (high tech is another story, outside most of us here). Nitrogen must be in the form of ammonia/ammonium, not nitrate, for the vast majority of aquatic plants. This is why fast growing plants such as surface plants are often called "ammonia sinks;" the amount of ammonia/ammonium they can take up is rather amazing. But they do nottake up nitrate unless ammonium, then nitrite, are insufficient to balance. For most of us with natural systems the fish plus the decomposition of organics in the substrate will provide all the ammonium to balance. And the latter is the primary source of carbon as CO2. Some plants are able to use bicarbonates (example, Vallisneria species which are native to the rift lakes), some (example mosses I believe) are not. Some will turn to bicarbonates if CO2 is inadequate.

Some nutrients are taken up exclusively from the water, via the leaves. Others via the roots.

Edit. In re-reading, I see I missed something I especially wanted to point out. Nitrate is harmful to fish. The species, the level and the exposure time can all factor in with respect to its effects. It is perhaps best to consider it as a weakening agent to fish, which allows other problems to have more of a detrimental effect on the fish than would otherwise (without nitrates) be easily handled. This is why nitrate should not be added as a plant nutrient.
 
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Lots of good info in this thread!

I’m especially interested in the use of bicarbonates as a source of carbon…there are only specific species of plants that can do this?
 
CarissaT said:
I’m especially interested in the use of bicarbonates as a source of carbon…there are only specific species of plants that can do this?
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Yes. Studies have shown that the faster an aquatic plant can uptake carbon, the faster it will grow. Obtaining carbon is often a problem for aquatic plants, and some have devised various methods for do so. One of these is the uptake of carbon from bicarbonates. Not surprisingly, the plants best able to do this are those that come from hard alkaline waters. A good example is Vallisneria which is native to the African rift lakes.

According to Diana Walstad, about half of the aquatic plants studied were able to use bicarbonates, and the other half could not. However, plants preferred CO2 to bicarbonates 10 to 1, probably because the uptake of bicarbonate requires more work by the plant and plants tend to want to spend their energy on flowering and reproducing rather than wasting it when not necessary. Many amphibious plants cannot use bicarbonates well, and they may have chosen the aerial advantage (allowing them to uptake CO2 from the air).
 
Too much vague information. How much nitrate; how much fertilizer; if the nitrate went from 0 to 10 after fertilization it is fine - esp since it should then slowly lower between fertilizer dosage; if the nitrate went from 5 to 1000; then it is awful and you need to do 100% water change and you dumped 10 bottles of fertlizer into the tank.
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The swords will do best with root tabs; the other plants will require some sort of general fertilizer. A lot of folks recommend thrive; others api and some sachem.
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My guess reading between the line is this is a newish tank and there was very little for the platns to consume. As the tank ages you will need less macros but still a steady dosage of micro.
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Don't worry about the co2 stuff - yes you could inject co2 (DO NOT USE bottle CO2 like excel it is false advertising and bad for the fishes); however for the plants you don't need co2 and you can do just fine without co2. Also don't make the mistake of thinking co2 will solve all your problems - there are other issues you have to deal with when injecting co2.
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Don't worry about micro/macro at this stage; just buy a general fertlizer.
 
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Yes if you start injecting co2 then the fertilization needs go up a lot which would only compound the problem. CO2 speeds everything up and great if you want super fast growth but that means you have to be totally on top of fertilizer needs…and if co2 levels drop you have to fix it immediately or massive die off starts occurring. Been there, done that. I used to do diy co2 injection which ends up with a lot of peaks and valleys, and because it’s so hard to keep stable I had major die off more than once.

Just my 2 cents on Excel, for me it works great for improving plant growth and reducing algae, and I’ve never seen any effects on the fish. There are anecdotal reports of fish deaths with it’s use, but no consensus. One person will have problems, and ten others will have no problems with the same dose and species. Based on that there’s got to be some other variable that’s creating an adverse chemical reaction in rare cases.
 
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Byron said:
Plants require 17 nutrients to grow (assuming the light is of sufficient intensity for the plant species, and the correct spectrum). Macros are oxygen, phosphorus, potassium, sulphur, calcium, hydrogen, carbon, magnesium and nitrogen. Micros are boron, iron, chloride, nickel, copper, manganese, zinc and molybdnum. If some of these, especially some of the micronutrients, are in excess, plants can shut down assimilation of certain other nutrients, creating an insufficiency. This is why the nutrients need some form of being in proportion, which is why not all fertilizers are advisable. And why dosing any single nutrient can be more harm than good.

Phosphorus will be more than sufficient from fish foods, assuming a normally-stocked aquarium using a natural or low-tech method (high tech is another story, outside most of us here). Nitrogen must be in the form of ammonia/ammonium, not nitrate, for the vast majority of aquatic plants. This is why fast growing plants such as surface plants are often called "ammonia sinks;" the amount of ammonia/ammonium they can take up is rather amazing. But they do nottake up nitrate unless ammonium, then nitrite, are insufficient to balance. For most of us with natural systems the fish plus the decomposition of organics in the substrate will provide all the ammonium to balance. And the latter is the primary source of carbon as CO2. Some plants are able to use bicarbonates (example, Vallisneria species which are native to the rift lakes), some (example mosses I believe) are not. Some will turn to bicarbonates if CO2 is inadequate.

Some nutrients are taken up exclusively from the water, via the leaves. Others via the roots.

Edit. In re-reading, I see I missed something I especially wanted to point out. Nitrate is harmful to fish. The species, the level and the exposure time can all factor in with respect to its effects. It is perhaps best to consider it as a weakening agent to fish, which allows other problems to have more of a detrimental effect on the fish than would otherwise (without nitrates) be easily handled. This is why nitrate should not be added as a plant nutrient.
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If you don’t add nitrate, what do you use for nitrogen?
 
CarissaT said:
Yes if you start injecting co2 then the fertilization needs go up a lot which would only compound the problem. CO2 speeds everything up and great if you want super fast growth but that means you have to be totally on top of fertilizer needs…and if co2 levels drop you have to fix it immediately or massive die off starts occurring. Been there, done that. I used to do diy co2 injection which ends up with a lot of peaks and valleys, and because it’s so hard to keep stable I had major die off more than once.

Just my 2 cents on Excel, for me it works great for improving plant growth and reducing algae, and I’ve never seen any effects on the fish. There are anecdotal reports of fish deaths with it’s use, but no consensus. One person will have problems, and ten others will have no problems with the same dose and species. Based on that there’s got to be some other variable that’s creating an adverse chemical reaction in rare cases.
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excel is an algaecide it does kill algae but it doesn't add more than a trace of co2 to the aquarium. There has been several tests - i think aquariumcoop has one on line if you look at their blogs that show they found almost no co2 from use of excel. Anyway you can get quite decent plant growth without co2 as shown in these two 29s:

w29_nov_11.jpgb29a.jpg
 
CarissaT said:
If you don’t add nitrate, what do you use for nitrogen?
Click to expand...

Terrestrial plants and aquatic plants have differing nutrient requirements. Both need nitrogen obviously, but whereas terrestrial plants take up nitrate via the roots from the soil (or water if hydroponic), the vast majority of aquatic plants do not take up nitrate but ammonia/ammonium, and via the leaves not the roots. They will only turn to nitrate if ammonia/ammonium and nitrite are no longer available, and assuming the nitrogen is then the minimizing factor. Therefore, nitrate should never be added to a low-tech or natural planted tank because (a) it harms the fish, and (b) the plants will not use it unless the light intensity is high, and all nutrients including CO2 is sufficient to balance. This means adding diffused CO2 because the normal level of CO2 in most fish tanks will be sufficient to balance low and moderate lighting but not high light. In scientific studies where aquatic plants were offered both nitrate and ammonium, 30 species preferred ammonium while only four preferred nitrate.

In one study (cited in Walstad) when Elodea nuttallii was placed in a mixture of equal parts ammonium and nitrates, the plant removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched; only when the ammonium was gone did the plants begin to take up nitrate, and at a much slower rate because of the necessary conversion process.

All plants use the N from ammonium—not nitrates—to produce their amino acids and proteins. If a plant takes up nitrate, it must convert the nitrate to ammonium in an energy-requiring process called ‘nitrate reduction.’ Plants must expend essentially the same amount of energy (83 Kcal/mol) that the nitrifying bacteria gained in order to convert nitrates back to ammonium. Clearly, we will have better and faster growth from aquatic plants from ammonium than if we force them to use nitrate. Though this forcing is unlikely in most natural planted tanks because the ammonia/ammonium produced by respiration of fish and decomposition of organics in the substrate will in most tanks be more than sufficient. Fast growing plants, especially floating plants, are often termed "ammonia sinks" for good reason.

The plants remove ammonia/ammonium faster than the nitrifying bacteria. And they do it non-stop, in light and in total darkness. Aquatic plants need ammonium to synthesize proteins. The plants also have the ability to store ammonium in their cell vacuoles. In one study, the vacuoles of Nitella clavata were found to contain over 2,400 mg/l of ammonium.
 
Byron said:
Terrestrial plants and aquatic plants have differing nutrient requirements. Both need nitrogen obviously, but whereas terrestrial plants take up nitrate via the roots from the soil (or water if hydroponic), the vast majority of aquatic plants do not take up nitrate but ammonia/ammonium, and via the leaves not the roots. They will only turn to nitrate if ammonia/ammonium and nitrite are no longer available, and assuming the nitrogen is then the minimizing factor. Therefore, nitrate should never be added to a low-tech or natural planted tank because (a) it harms the fish, and (b) the plants will not use it unless the light intensity is high, and all nutrients including CO2 is sufficient to balance. This means adding diffused CO2 because the normal level of CO2 in most fish tanks will be sufficient to balance low and moderate lighting but not high light. In scientific studies where aquatic plants were offered both nitrate and ammonium, 30 species preferred ammonium while only four preferred nitrate.

In one study (cited in Walstad) when Elodea nuttallii was placed in a mixture of equal parts ammonium and nitrates, the plant removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched; only when the ammonium was gone did the plants begin to take up nitrate, and at a much slower rate because of the necessary conversion process.

All plants use the N from ammonium—not nitrates—to produce their amino acids and proteins. If a plant takes up nitrate, it must convert the nitrate to ammonium in an energy-requiring process called ‘nitrate reduction.’ Plants must expend essentially the same amount of energy (83 Kcal/mol) that the nitrifying bacteria gained in order to convert nitrates back to ammonium. Clearly, we will have better and faster growth from aquatic plants from ammonium than if we force them to use nitrate. Though this forcing is unlikely in most natural planted tanks because the ammonia/ammonium produced by respiration of fish and decomposition of organics in the substrate will in most tanks be more than sufficient. Fast growing plants, especially floating plants, are often termed "ammonia sinks" for good reason.

The plants remove ammonia/ammonium faster than the nitrifying bacteria. And they do it non-stop, in light and in total darkness. Aquatic plants need ammonium to synthesize proteins. The plants also have the ability to store ammonium in their cell vacuoles. In one study, the vacuoles of Nitella clavata were found to contain over 2,400 mg/l of ammonium.
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I find this information troubling - not that it isn't correct but on how fertlizers can be effective for plants. ammonium i believe (though i could be mistaken) is not great for fishes - perhaps worse than nitrate. Of coruse with a heavy fish load that might help with plants but you don't want ot over do it for the health of the fishes. ... to be honest once my tanks are established - 'cept with a few specific plants i rarely see benefits from fertlizing more than once every 4 or 6 weeks and that probably has more to do with micros. I suppose some of the nutrients might be comming into the tank from frequent water changes but i would have to become more sophisticated and have an analysis done of the water to determine if it has any micros and well that is just a step too far for me. I should just be happy that things grow.
 
Byron said:
Terrestrial plants and aquatic plants have differing nutrient requirements. Both need nitrogen obviously, but whereas terrestrial plants take up nitrate via the roots from the soil (or water if hydroponic), the vast majority of aquatic plants do not take up nitrate but ammonia/ammonium, and via the leaves not the roots. They will only turn to nitrate if ammonia/ammonium and nitrite are no longer available, and assuming the nitrogen is then the minimizing factor. Therefore, nitrate should never be added to a low-tech or natural planted tank because (a) it harms the fish, and (b) the plants will not use it unless the light intensity is high, and all nutrients including CO2 is sufficient to balance. This means adding diffused CO2 because the normal level of CO2 in most fish tanks will be sufficient to balance low and moderate lighting but not high light. In scientific studies where aquatic plants were offered both nitrate and ammonium, 30 species preferred ammonium while only four preferred nitrate.

In one study (cited in Walstad) when Elodea nuttallii was placed in a mixture of equal parts ammonium and nitrates, the plant removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched; only when the ammonium was gone did the plants begin to take up nitrate, and at a much slower rate because of the necessary conversion process.

All plants use the N from ammonium—not nitrates—to produce their amino acids and proteins. If a plant takes up nitrate, it must convert the nitrate to ammonium in an energy-requiring process called ‘nitrate reduction.’ Plants must expend essentially the same amount of energy (83 Kcal/mol) that the nitrifying bacteria gained in order to convert nitrates back to ammonium. Clearly, we will have better and faster growth from aquatic plants from ammonium than if we force them to use nitrate. Though this forcing is unlikely in most natural planted tanks because the ammonia/ammonium produced by respiration of fish and decomposition of organics in the substrate will in most tanks be more than sufficient. Fast growing plants, especially floating plants, are often termed "ammonia sinks" for good reason.

The plants remove ammonia/ammonium faster than the nitrifying bacteria. And they do it non-stop, in light and in total darkness. Aquatic plants need ammonium to synthesize proteins. The plants also have the ability to store ammonium in their cell vacuoles. In one study, the vacuoles of Nitella clavata were found to contain over 2,400 mg/l of ammonium.
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Ok so to boil it down, you feel there is enough ammonia produced by the fish to provide for the plants nitrogen needs? Unless someone is doing high light and co2 in which case you have no choice but fertilize with nitrate.

Agreed that 0 nitrate is best for fish, if that‘s all someone is interested in. However in the vast majority of real life situations I would think that a small amount of nitrate is probably not the most concerning factor when it comes to fish health.

I suppose this theory could be tested by putting plants and fish in a fresh tank (that presumably would have little to no nitrifying bacteria), adding a small amount of nitrate, and then testing to see if that nitrate disappears.

Of course there are a lot of variables involved with any specific situation, some of which would be fish load, feeding habits, lighting, and the amount and type of plants.

In a saltwater environment the ideal is to complete the cycle using live rock, thus eliminating all nitrates. Many corals will not do well in the presence of any nitrates.
 
anewbie said:
I find this information troubling - not that it isn't correct but on how fertlizers can be effective for plants. ammonium i believe (though i could be mistaken) is not great for fishes - perhaps worse than nitrate. Of coruse with a heavy fish load that might help with plants but you don't want ot over do it for the health of the fishes. ... to be honest once my tanks are established - 'cept with a few specific plants i rarely see benefits from fertlizing more than once every 4 or 6 weeks and that probably has more to do with micros. I suppose some of the nutrients might be comming into the tank from frequent water changes but i would have to become more sophisticated and have an analysis done of the water to determine if it has any micros and well that is just a step too far for me. I should just be happy that things grow.
Click to expand...

Ammonium is harmless to fish. Which is why in tanks with an acidic pH, the ammonia is basically ammonium and thus harmless. And nitrate is much worse for fish than ammonium ever could be. The amount of ammonia/ammonium is more than one might think, but with our test kits you cannot have above 0 unless there is something serious compromised. At the same time, it would be basically impossible for the plants to not take up all the ammonia, all else being equal. For example, some worry about adding fish to a "cycled" tank, that it will cause a mini-cycle. With fast growing plants present and "growing," it would be virtually impossible to add so many fish at one time that you would ever be able to detect ammonia. This is another reason why healthy plants are so beneficial. Floating plants are best at this, they really are "ammonia sinks."

It is possible to have a balanced tank requiring no fertilizers for the plants. It depends upon the plant species, how many there are, and the fish load. Nutrients come from fish foods, and from natural processes (the production of CO2 for example), as well as from water changes depending upon the GH (calcium and magnesium) in the source water. I found that I required some supplementation in my tanks, and for this one should always and only ever use a comprehensive aquarium plant fertilizer.

Use the condition of the plants to assess whether or not they need supplementation. I found that my larger swords needed substrate tabs, and to keep my floating Ceratopteris in good condition I needed to use a comprehensive liquid, but minimally.
 
anewbie said:
excel is an algaecide it does kill algae but it doesn't add more than a trace of co2 to the aquarium. There has been several tests - i think aquariumcoop has one on line if you look at their blogs that show they found almost no co2 from use of excel. Anyway you can get quite decent plant growth without co2 as shown in these two 29s:

View attachment 165166View attachment 165167
Click to expand...

Agreed there are many beautiful tanks that don’t use any supplemental carbon. However it’s the only thing that has essentially eliminated most algae growth in my tanks. Whether the plants grow better due to carbon or due to the algaecidal effect, or both, I don’t know. I just know what works for me.
 
CarissaT said:
Ok so to boil it down, you feel there is enough ammonia produced by the fish to provide for the plants nitrogen needs? Unless someone is doing high light and co2 in which case you have no choice but fertilize with nitrate.
Click to expand...

Assuming most of us have a decent number of fish in an aquarium, yes, with a natural or low-tech method planted tank there will without question always be sufficient ammonia. In most situations, the CO2 will be the limiting factor. It was for me. I do not believe in supplementing CO2 in any form because this too does harm the fish over time, that is now accepted. So I relied solely on the natural CO2. Once you get into a high-tech system, the ammonia will be used up, though it depends upon the plant load and fish load, and the other factors like light, CO2, nutrient dosing. Nitrate is commonly added, but the plants have to use considerable energy converting it back into ammonium in order to use it.

CarissaT said:
Agreed that 0 nitrate is best for fish, if that‘s all someone is interested in. However in the vast majority of real life situations I would think that a small amount of nitrate is probably not the most concerning factor when it comes to fish health.
Click to expand...

It depends upon the nitrate level, the fish species, and the exposure time. None of the tropical fish species we maintain in aquaria have nitrate in their habitat waters, or if they do it is below 1 ppm; I have never seen higher readings anywhere. So biology tells us that these fish are designed to function at their best in nitrate-free water, just as they cannot have ammonia or nitrite. As for the effects on fish, this is not easy to say because few studies have been done with ornamental fish. Nitrate studies tend to focus on the commercial food fish industry. I discussed this nitrate issue a while back with Dr. Neale Monks, and he suggested it was a sort of general weakening of the fish, which in time would leave them susceptible to other issues that they would otherwise be able to easily deal with, but the detrimental effect of constant nitrate debilitated them. There is now evidence that diseases like Hole in the Head in cichlids occurs due to high nitrates. Cichlids are believed to be especially sensitive to nitrate, and 20ppm is the highest they should ever be, though here again the lower the better. Many smaller fish, especially wild caught, will not last long with nitrates this high. For all fish, nitrates cause them difficult in "living," and this will cause stress, and stress is directly responsible for 90% or more of all diseases our aquarium fish contract. So, it is logical to reduce stress, and lowering nitrates helps.

CarissaT said:
I suppose this theory could be tested by putting plants and fish in a fresh tank (that presumably would have little to no nitrifying bacteria), adding a small amount of nitrate, and then testing to see if that nitrate disappears.
Click to expand...

This has been done, it is the basis for all I have written. There are a hundred or more scientific studies referenced in Diana Walstad's book Ecology of the Planted Aquarium.
 
CarissaT said:
Agreed there are many beautiful tanks that don’t use any supplemental carbon. However it’s the only thing that has essentially eliminated most algae growth in my tanks. Whether the plants grow better due to carbon or due to the algaecidal effect, or both, I don’t know. I just know what works for me.
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There is no doubting that Excel kills algae, at least sometimes. But that alone should cause us to never use it in a tank with fish. It contains a derivative of glutaraldehyde, a highly toxic disinfectant. Used at recommended dosage, Vallisneria plants will usually be killed, along with some other plants. Some bacteria can be harmed--glutaraldehyde is after all used in ship ballasts to kill bacteria. And in hospitals to sterilize medical instruments. I would never use this in an aquarium with fish.
 
Byron said:
There is no doubting that Excel kills algae, at least sometimes. But that alone should cause us to never use it in a tank with fish. It contains a derivative of glutaraldehyde, a highly toxic disinfectant. Used at recommended dosage, Vallisneria plants will usually be killed, along with some other plants. Some bacteria can be harmed--glutaraldehyde is after all used in ship ballasts to kill bacteria. And in hospitals to sterilize medical instruments. I would never use this in an aquarium with fish.
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It’s difficult to really know what’s going on with Excel since the company won’t release the chemical formula. Being related or derived from glutaraldehyde doesn’t in and of itself make it toxic to fish, just as petroleum jelly isn’t toxic because it comes from petroleum and carbon dioxide isn’t toxic to breathe even though it’s only one atom away from carbon monoxide. I think there are a lot of chemical reactions going on with it in various situations making it nearly impossible to make a broad statement that is is definitely toxic to fish. Maybe it is always slightly toxic, maybe it is toxic in the presence of certain other compounds, from what I’ve read nobody actually knows, except maybe the company but of course they won’t say.
 
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