paludarium;44290 said:
IHe pointed out that high KH or HCO3 levels might hinder iron uptakes of the plants either in roots zone or leaves, and the transport of iron within the plants, cause formation of FePO4 in the plants, and lastly disrupt NO3 uptakes. Therefore KH should not be kept too high, especially for the trouble plants. However the book also indicates that nitrate levels should keep low for some plants, especially when the KH is high.
I am confused..... I only know that KH issue is related to CO2...
Regards,
Erich
I think you'd do well to stick with what you know there, as it's right on target.
I do not dispute the observation that certain species do poorly in higher KH's.
No one does I think.
How the KH and CO2 are affected is a curious thing. HCO3 blocking CO2, or some effect there seems more likely.
Is the pH of your blood able to change because we put you in say Mono Lake, CA a with a pH of 10.1 or in Lake Palcid in Florida with a pH of 4.7?
Endogenous homoestatsis
within the plant is a very very very different process than external environment. Plants, virtually all organisms would perish if they where subjected to those same conditions, even a bacterium does this.
They have to push against a concentrational gradient.
Plants do this with Salts all the time. They are also quite good at it. They have excellent "gate keeping" of various chemicals inside them, many of which if left alone and not controlled, would kill everything in the plant. This sounds more like poor Biological understanding on his part from what you have stated here.
NO3 has no impact on plants over a wide range other than generally more growth with increase in concentrations up to about 30-40ppm for aquatic species, in fact, 98% of aquatic plants grown commercially, including perhaps 100% of thr German supplies from growers, comes from Tropica which uses standard type of Hydroponics to grow plants, the average concentrations for most Hoagland modified solutions is 200-240ppm of NO3.
If you limit NO3, then you also limit all other down stream nutrients, and you can also have a case where strong NO3 limits CO2 demand, just like with PO4 if the limitation is stronger than the CO2 limitation.
Maybe it was CO2, not anything to do with NO3?
How did he know the CO2 was good or not? Unless you have a reference to compare to and a good stable tank, you cannot say, you can speculate, but you cannot say.
Even a person with no experience can reason that if you want to test and see if these claims are true, all you need to do is show a few cases where this occurs under high NO3 and high KH, and you can clearly see the hypothesis is not correct.
Some species of plants do poorly at high KH, I do not dispute that, but Fe can be added using DTPA and other chelators that are not hindered at higher pH/KH's, and the internal environment is not exposed either.
Also, if you plan on setting up any test, you MUST test all sides, not just the ones you happen to "believe". Again, common sense prevails here=>
For any nutrient test you must be able a non limiting reference, and a severely limiting reference, all other results will fall in between. I can tell real quick if someone has not done a non limiting reference
Why?
I've done many of them and with most every species I can get my grubbly little hands on.
Here's a high NO3(30ppm), high KH(11 degrees), high GH too(24 degrees), but CO2 rich and non limiting nutrients:
I thinkj he might need to be a lot more specific and give specific ppm;'s, KH's and specific species that can or cannot be grown at high KH's say 5-7 degrees or higher.
Then even that is speculation, we ask around and see if anyone is growing say Tonina well at a higher KH than say 6-7 degrees and then compare. We must start with the observations and look at all sides, not just what we might want to believe or fall prey to repeating a good myth.
I know NO3 over a wide range has no direct impacts on plant health unless it gets too low, some species do much worse than others at lower ppm of NO3.
I know of no plant that does poorly at say 30ppm of NO3.
None.
So that issue can be ruled out pretty effectively.
Fe, I think that also can be dealt with.
CO2 and KH and the effects, that's tougher. But here's how you could answer part of the issue: grow the plants in high KH hydroponically, as the CO2 will be non limiting and KH of the the air....is well, not present.
If they still grow well at high KH tap water, well, then it's more likley, that it's a CO2 uptake issue.
You also need to have nutrients in the sediments and in the water and then just in either location. You can speculate, ask, pose the question has anyone been able to grow in these conditions this species well? Few do that however, they just think because they personally have some correlation, that is means that there is cause. It does not.
A good myth is hard to kill.
Regards,
Tom Barr