newbie ?s

[Cermet]

Not sure of the post, either; but plants can be killed by high ammonia and nitrites are just terrible for plants. Mommy1 is correct, no way ammonia levels could reach harmful levels for plants with fish.

Plants prefer nitrates and do not easily use ammonia.

[funkman262]

Plants prefer nitrates and do not easily use ammonia.

That statement is right and wrong. Yes, terrestrial plants prefer nitrates and are able to consume it at higher rates than ammonia. However, aquatic plants don't consume nitrate at all. The plant must convert the nitrite and nitrate to ammonium first (wasting energy doing so) thus ammonium is clearly the preferred nitrogen source.

Here's a very interesting article written by Diana Walstad describing plant filtration: http://www.theaquariumwiki.com/Plants_and_Biological_Filtration

[Cermet]

Where is my statement wrong? Nitrites are not good for plants and ammonia is toxic at high levels - both true statements as far as I've read. Relative to nitrates, you are saying that every single plant fert mfg. is wrong since they include nitrates? Most people with plants dose nitrate, never ammonia ... .

The article you cite says plants have no problems using nitrates; only that ammonia is eaier to uptake. Still don't see where I'm wrong ... confused here.

Also, ammonia will kill fish very quickly, is bad for people to breath, so, can't see anyone using it; also, the article is dead wrong on this point - ammoina is NEVER used directly by plants - ammonia is a gas at room temperature unless in a solution ... they mean a complex containing ammonia.

[Honey Badger 1]

We don't have to dose ammonia, the fish do that for us.

[Cermet]

We don't have to dose ammonia, the fish do that for us.

Wow! I'd never would have guessed that!

[funkman262]

Where is my statement wrong? Nitrites are not good for plants and ammonia is toxic at high levels - both true statements as far as I've read. Relative to nitrates, you are saying that every single plant fert mfg. is wrong since they include nitrates? Most people with plants dose nitrate, never ammonia ... .

The article you cite says plants have no problems using nitrates; only that ammonia is eaier to uptake. Still don't see where I'm wrong ... confused here.

Also, ammonia will kill fish very quickly, is bad for people to breath, so, can't see anyone using it; also, the article is dead wrong on this point - ammoina is NEVER used directly by plants - ammonia is a gas at room temperature unless in a solution ... they mean a complex containing ammonia.

Umm... First off, you said, and I quote, "Plants prefer nitrates and do not easily use ammonia" which I simply explained is incorrect for aquatic plants. I said that aquatic plants PREFER ammonium, and have to convert nitrate to ammonium in order to utilize it. Secondly, I said nothing about the toxicity of these nitrogen compounds to fish as I was simply correcting your statement so that misinformation isn't being spread. Thirdly, the article does in fact discuss how plants have problems using nitrates: "The energy required for nitrate reduction is equivalent to 23.4% of the energy obtained from glucose combustion. Thus, if nitrifying bacteria in biological filters convert all available ammonium to nitrates, plants will be forced—at an energy cost—to convert all the nitrates back to ammonium.". Lastly, I NEVER said anything about fert manufacturers being wrong. The reason that we dose nitrate is because it's safer for fish. Honestly though, if I had a plant-only tank, I would dose ammonia instead of nitrate so that the plants don't have to use up energy converting the nitrate to ammonium. You must have just skipped the entire article and went straight into defensive mode instead of trying to learn some valuable information written by an incredibly respected member of the hobby.

EDIT: Sorry, I missed your last point. If you read back, I've been very specific in that they readily consume ammoniUM, which is an ion in solution and more abundant than ammoniA at the pH that we keep our tanks, and very readily consumed by plants.