Hole In Head Syndrome

[Byron]

Plants can be excellent indicators for nitrates. Even before they display deficiency symptoms you can gauge your nitrates level by seeing how the leaves color under the light. This is only true if you are low enough however, above a certain point all you can see is that there is ample nitrates for the plants, but there could be way too much and you'd have no idea.
Lowering nitrates levels leads plants to react more strongly to the light, they will become redder/more coppery and do so from further away from the light compared to when nitrates are higher.
This is easier to spot on plants like bacopas, many rotalas, and others with similar tendencies.
Once you've learned to interpret it, it is quite accurate, vastly more so than a common drop test.
EDIT: A small thing on the subject: https://www.2hraquarist.com/blogs/fertilize-planted-tank/nitrate-limitation

This is misleading again. Only in a high-tech system where you have mega light, diffused CO2, and more regular nutrient dosing will plants take up nitrate as their nitrogen source. It is not applicable to those having low-tech or natural method planted tanks with fish the prime concern.

Many aquarists with the low-tech planted tanks, like me, have zero nitrate or depending upon the fish load very, very low nitrate. You cannot measure nitrate levels from the plants. You can assume that in such a system if the plants are doing well they are using most of the ammonia/ammonium, which means less for the nitrifying bacteria/archaea, and thus less nitrite and less nitrate down the line. But there is no way without measuring nitrate that you can say what the level is in that tank.

Fast growing aquatic plants, and here floating plants are ideal, can be termed "ammonia sinks" because of the incredible amount of ammonia/ammonium they assimilate. They are faster at grabbing it than the nitrifiers, which leads to less nitrite and nitrate. If you start adding nitrate, the plants will ignore it until such time as the ammonia/ammonium is no longer adequate. There is evidence that plants will take up nitrite before nitrate, due to the complex use of energy.

 

[Palemon]

I don't see where we disagree here. I only explained my method, in my tank, where it works. And then given more informations when the notion was challenged, that is all.
By the way it doesn't require mega-light, an "upper medium" lighting is enough. Such as those that come in most premade tanks. It only shifts the threshold where it occurs, but it still occurs.

Many aquarists with the low-tech planted tanks, like me, have zero nitrate or depending upon the fish load very, very low nitrate. You cannot measure nitrate levels from the plants. You can assume that in such a system if the plants are doing well they are using most of the ammonia/ammonium, which means less for the nitrifying bacteria/archaea, and thus less nitrite and less nitrate down the line. But there is no way without measuring nitrate that you can say what the level is in that tank.

Once again, we agree. The thing is, my fish load isn't enough to produce the ammonia needed by the plants, which is why I close the difference with KNO3. Which, you'll agree, is quite a testament to how low the nitrates and its precursors are. No?

 

[GaryE]

BTW - for araguia (however you spell them!) - they come from really high current water, and were aggressive here when I had them. A friend who has a group in a 360 with massive turnover from a large laminar flow pump has a different experience. I've watched them there and they are a peaceful as can be.

 

[Palemon]

Wild Araguaiae such as mine can be really mean yes. On the contrary their offspring weren't aggressive, granted that they weren't fully grown when I sold them.
However if there's no other similarly shaped cichlid in the tank, they are absolutely devoid of aggression outside of reproduction, even wild ones. At least it has been my experience.

 

[Byron]

I don't see where we disagree here. I only explained my method, in my tank, where it works. And then given more informations when the notion was challenged, that is all.
By the way it doesn't require mega-light, an "upper medium" lighting is enough. Such as those that come in most premade tanks. It only shifts the threshold where it occurs, but it still occurs.


Once again, we agree. The thing is, my fish load isn't enough to produce the ammonia needed by the plants, which is why I close the difference with KNO3. Which, you'll agree, is quite a testament to how low the nitrates and its precursors are. No?

High tech tanks need much more intense lighting than I have ever been willing to subject my fish to, as I know the detriment light has for most forest fish. With the low/moderate lighting I have used for 30 years, I would not get plants as shown in the photographs. Red leaf plants are red because they reflect red light, and since red light is the primary driver of photosynthesis (the other is blue), you need more intense lighting in order to have enough both for photosynthesis and colour. I stayed with the plants that managed under my conditions because the fish were of more importance than the plants.

No, I do not think you can measure nitrate levels by plants. You've no idea how much nitrate may be in the system unless you test it.

 

[Palemon]

Just a quick update to let you know that neither metronidazole nor quinolones and their accompanying measures have worked, she died a few days ago. Thank you everyone for trying.