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[APD] RE: K+ measurement/minimum requirements for plants

> I guess there's a reason that all the old manuals, and
> some of the new, promote using soft water for alot of
> the plants once considered difficult. Doesn't it make
> sense to find the *minimum* critical value for dosing
> K+? I certainly have seen improved growth, in every
> respect, when using much less K+.  
> It has been pointed out to me that some nutrients are
> best utilized when in excess, CO2 for example. Is K+
> one of these?  
> Best wishes,
> John Wheeler

Well minimum K+ relative to _what_?
The ratio relative to other nutrients is a good adaptation.

N:P ratios for aquatic macrophytes is 10:1.
A 1:1 ratio of N:K+ will lead to excess since most plants are 1.5N:1 K+.

Mr Ghori suggested a 10:1:10, NPK ratio which is a nice easy simple number
and seems like it should be adopted vs the older 20-30ppm of K and the
range but this can be put into a context of a range also, just another way
of saying it.

Even if there are some plant differences, this should make up for it and
good growth will be dependent on N and P rather than traces/K+ etc.
K+ makes a rather poor choice due to testing issues ansd release from the
leaves for limiting an aquarium.

So yes, like CO2, PO4 perhaps, and K+, generally all things are in excess
and might drop down for a day or two etc mbut the over supply is enough to
keep the plant happy.

I think many folks seem to feel the minmum amounts of nutrients is somehow
going to produce less algae.
Nope.Good plant growth will though.

It also is a PITA to micro mange your tank so much attempting to outwit
algae a little by dosing daily, skirting the minimum ranges with nutrients.
It can be done well using a balanced fish load, less lighting or a non CO2
method quite well, but these variable need to be taken into consideration
when the aquarist wants to do a certain routine/method that is right for
Tom Barr 

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